MLX90614ESF-BAA-000-TU - Melexis - Datasheet.Directory

MLX90614 family

Datasheet

Single and Dual Zone

Infra Red Thermometer in TO-39

REVISION 11 - JUNE 15, 2017

3901090614

Features and Benefits

 Small size, low cost

 Easy to integrate

 Factory calibrated in wide temperature

range:

 -40°C…+125˚C for sensor temperature and

-70°C…+380˚C for object temperature.

 High accuracy of 0.5°C in a wide

temperature range (0°C…+50°C for both Ta

and To)

 High (medical) accuracy calibration

 Measurement resolution of 0.02°C

 Single and dual zone versions

 SMBus compatible digital interface

 Customizable PWM output for continuous

reading

 Available in 3V and 5V versions

 Simple adaptation for 8V…16V applications

 Sleep mode for reduced power

consumption

 Different package options for applications

and measurements versatility

 Automotive grade

Application Examples

 High precision non-contact temperature

measurements

 Thermal Comfort sensor for Mobile Air

Conditioning control system

 Temperature sensing element for

residential, commercial and industrial

building air conditioning

 Windshield defogging

 Automotive blind angle detection

 Industrial temperature control of moving

parts

 Temperature control in printers and

copiers

 Home appliances with temperature control

 Healthcare

 Livestock monitoring

 Movement detection

 Multiple zone temperature control – up to

127 sensors can be read via common 2

wires

 Thermal relay / alert

 Body temperature measurement

Ordering Information

Part No.

MLX90614

Temperature

Code

E (-40°C...85°C)

K (-40°C…125°C)

Package

Code

SF (TO-39)

- Option Code

- X X X

(1) (2) (3)

Standard

part

-000

Packing

form

-TU

(1) Supply Voltage/ Accuracy

A - 5V

B - 3V

C - Reserved

D - 3V medical accuracy

(2) Number of thermopiles:

A – single zone

B – dual zone

C – gradient compensated*

(3) Package options:

A – Standard package

B – Reserved

C – 35° FOV

D/E – Reserved

F – 10° FOV

G – Reserved

H – 12° FOV (refractive lens)

I – 5° FOV

K – 13°FOV

Example:

MLX90614ESF-BAA-000-TU * : See page 2

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

REVISION 11 - JUNE 15, 2017

3901090614

1. Functional diagram

Figure 1: Typical application schematics

2. General Description

The MLX90614 is an Infra Red thermometer for non-

contact temperature measurements. Both the IR

sensitive thermopile detector chip and the signal

conditioning ASSP are integrated in the same TO-39 can.

Thanks to its low noise amplifier, 17-bit ADC and

powerful DSP unit, a high accuracy and resolution of the

thermometer is achieved.

The thermometer comes factory calibrated with a digital

PWM and SMBus (System Management Bus) output.

As a standard, the 10-bit PWM is configured to

continuously transmit the measured temperature in

range of -20…120˚C, with an output resolution of 0.14˚C.

The factory default POR setting is SMBus.

The MLX90614 is built from 2 chips developed and manufactured by Melexis:

 The Infra Red thermopile detector MLX81101

 The signal conditioning ASSP MLX90302, specially designed to process the output of IR sensor.

The device is available in an industry standard TO-39 package.

Thanks to the low noise amplifier, high resolution 17-bit ADC and powerful DSP unit of MLX90302 high accuracy and

resolution of the thermometer is achieved. The calculated object and ambient temperatures are available in RAM of

MLX90302 with resolution of 0.01°C. They are accessible by 2 wire serial SMBus compatible protocol (0.02°C

resolution) or via 10-bit PWM (Pulse Width Modulated) output of the device.

The MLX90614 is factory calibrated in wide temperature ranges: -40°C…125°C for the ambient temperature

and -70°C…380°C for the object temperature.

The measured value is the average temperature of all objects in the Field Of View of the sensor. The MLX90614 offers

a standard accuracy of ±0.5˚C around room temperatures. A special version for medical applications exists offering an

accuracy of ±0.2˚C in a limited temperature range around the human body temperature.

It is very important for the application designer to understand that these accuracies are only guaranteed and

achievable when the sensor is in thermal equilibrium and under isothermal conditions (there are no temperature

differences across the sensor package). The accuracy of the thermometer can be influenced by temperature

differences in the package induced by causes like (among others): Hot electronics behind the sensor, heaters/coolers

behind or beside the sensor or by a hot/cold object very close to the sensor that not only heats the sensing element in

the thermometer but also the thermometer package.

This effect is especially relevant for thermometers with a small FOV like the xxC and xxF as the energy received by the

sensor from the object is reduced. Therefore, Melexis has introduced the xCx version of the MLX90614. In these

MLX90614xCx, the thermal gradients are measured internally and the measured temperature is compensated for

them. In this way, the xCx version of the MLX90614 is much less sensitive to thermal gradients, but the effect is not

totally eliminated. It is therefore important to avoid the causes of thermal gradients as much as possible or to shield

the sensor from them.

As a standard, the MLX90614 is calibrated for an object emissivity of 1. It can be easily customized by the customer for

any other emissivity in the range 0.1…1.0 without the need of recalibration with a black body.

The 10-bit PWM is as a standard configured to transmit continuously the measured object temperature for an object

temperature range of -20°C…120°C with an output resolution of 0.14°C. The PWM can be easily customized for

virtually any range desired by the customer by changing the content of 2 EEPROM cells. This has no effect on the

factory calibration of the device.

J1

CON1

SCL

SDA

GND

Vdd

C1 value and type may differ

in different applications

for optimum EMC

U1

MLX90614

1

P W M

SDA

C1

M LX906 1 4 connection to SM Bus

4

Vss

SCL

Vz

MLX90614Axx : Vdd=4.5...5.5V

3

2

Vdd

0.1uF

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 3 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

The PWM pin can also be configured to act as a thermal relay (input is To), thus allowing for an easy and cost effective

implementation in thermostats or temperature (freezing / boiling) alert applications. The temperature threshold is

user programmable. In a SMBus system this feature can act as a processor interrupt that can trigger reading all slaves

on the bus and to determine the precise condition.

The thermometer is available in 2 supply voltage options: 5V compatible or 3V (battery) compatible. The 5V can be

easily adopted to operate from a higher supply voltage (8…16V, for example) by use of few external components (refer

to “Applications information” section for details).

An optical filter (long-wave pass) that cuts off the visible and near infra-red radiant flux is integrated in the package to

provide ambient and sunlight immunity. The wavelength pass band of this optical filter is from 5.5…14µm (except for

xCH and xCI type of devices which incorporate uncoated silicon lens).

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 4 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

3. Contents

Features and Benefits

Features and BenefitsFeatures and Benefits

Features and Benefits

................................

................................................................

................................

1

11

1

Application

Application Application

Application Examples

ExamplesExamples

Examples

................................

................................................................

................................

1

11

1

Ordering Information

Ordering InformationOrdering Information

Ordering Information

................................

................................................................

................................

1

11

1

1. Functional diagram

1. Functional diagram1. Functional diagram

1. Functional diagram

................................

................................................................

................................

2

22

2

2. General Description

2. General Description2. General Description

2. General Description

................................

................................................................

...............................................................

..............................................................

...............................

2

22

2

3. Contents

3. Contents3. Contents

3. Contents

................................

................................................................

................................................

................................

................

4

44

4

4. Glossary of Terms

4. Glossary of Terms4. Glossary of Terms

4. Glossary of Terms

................................

................................................................

..................................

....

..

7

77

7

5. Maximum ratings

5. Maximum ratings5. Maximum ratings

5. Maximum ratings

................................

................................................................

...................................

......

...

7

77

7

6. Pin definitions and descriptions

6. Pin definitions and descriptions6. Pin definitions and descriptions

6. Pin definitions and descriptions

................................

................................................................

.............................................

..........................

.............

8

88

8

7. Electrical Specifications

7. Electrical Specifications7. Electrical Specifications

7. Electrical Specifications

................................

................................................................

.........................................................

..................................................

.........................

9

99

9

7.1. MLX90614Axx ..................................................................................................................................... 9

7.2. MLX90614Bxx, MLX90614Dxx .......................................................................................................... 11

8. Detailed description

8. Detailed description8. Detailed description

8. Detailed description

................................

................................................................

............................................................

........................................................

............................

13

1313

13

8.1. Block diagram .................................................................................................................................... 13

8.2. Signal processing principle ............................................................................................................... 13

8.3. Block description ............................................................................................................................... 14

8.3.1. Amplifier ...................................................................................................................................... 14

8.3.2. Supply regulator and POR .......................................................................................................... 14

8.3.3. EEPROM ...................................................................................................................................... 14

8.3.4. RAM ............................................................................................................................................. 17

8.4. SMBus compatible 2-wire protocol ................................................................................................. 17

8.4.1. Functional description ................................................................................................................ 17

8.4.2. Differences with the standard SMBus specification (reference [1]) ........................................ 18

8.4.3. Detailed description ................................................................................................................... 18

8.4.4. Bit transfer .................................................................................................................................. 19

8.4.5. Commands .................................................................................................................................. 20

8.4.6. SMBus communication examples .............................................................................................. 20

8.4.7. Timing specification .................................................................................................................... 21

8.4.8. Sleep Mode ................................................................................................................................. 22

8.4.9. MLX90614 SMBus specific remarks ........................................................................................... 23

8.5. PWM .................................................................................................................................................. 24

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 5 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.5.1. Single PWM format ..................................................................................................................... 25

8.5.2. Extended PWM format ............................................................................................................... 26

8.5.3. Customizing the temperature range for PWM output ............................................................. 27

8.6. Switching Between PWM / Thermal relay and SMBus communication ........................................ 29

8.6.1. PWM is enabled .......................................................................................................................... 29

8.6.2. Request condition ....................................................................................................................... 29

8.6.3. PWM is disabled ......................................................................................................................... 29

8.7. Computation of ambient and object temperatures ....................................................................... 30

8.7.1. Ambient temperature Ta ............................................................................................................ 30

8.7.2. Object temperature To ............................................................................................................... 30

8.7.3. Calculation flow .......................................................................................................................... 31

8.8. Thermal relay .................................................................................................................................... 32

9. Unique

9. Unique 9. Unique

9. Unique Features

FeaturesFeatures

Features

................................

................................................................

..................................

....

..

33

3333

33

10. Performance Graphs

10. Performance Graphs10. Performance Graphs

10. Performance Graphs................................

................................................................

..........................................................

....................................................

..........................

34

3434

34

10.1. Temperature accuracy of the MLX90614 ...................................................................................... 34

10.1.1. Standard accuracy .................................................................................................................... 34

10.1.2. Medical accuracy ...................................................................................................................... 36

10.1.3. Temperature reading dependence on VDD ............................................................................ 36

10.2. Field Of View (FOV) ......................................................................................................................... 38

11. Applications Information

11. Applications Information11. Applications Information

11. Applications Information

................................

................................................................

...................................................

......................................

...................

42

4242

42

11.1. Use of the MLX90614 thermometer in SMBus configuration ...................................................... 42

11.2. Use of multiple MLX90614s in SMBus configuration ................................................................... 42

11.3. PWM output operation .................................................................................................................. 42

11.4. Thermal alert / thermostat ............................................................................................................ 43

11.5. High voltage source operation ....................................................................................................... 44

12. Application Comments

12. Application Comments12. Application Comments

12. Application Comments

................................

................................................................

......................................................

............................................

......................

45

4545

45

13. Standard information regarding manufacturability of Melexis products with different soldering

13. Standard information regarding manufacturability of Melexis products with different soldering 13. Standard information regarding manufacturability of Melexis products with different soldering

13. Standard information regarding manufacturability of Melexis products with different soldering

processes

processesprocesses

processes

................................

................................................................

............................................

........................

............

47

4747

47

14. ESD

14. ESD 14. ESD

14. ESD Precautions

PrecautionsPrecautions

Precautions

................................

................................................................

.................................

..

.

47

4747

47

15. FAQ

15. FAQ15. FAQ

15. FAQ

................................

................................................................

...................................................

......................................

...................

48

4848

48

16. Package Information

16. Package Information16. Package Information

16. Package Information

................................

................................................................

..........................................................

....................................................

..........................

50

5050

50

16.1. MLX90614xxA ................................................................................................................................. 50

16.2. MLX90614xCC ................................................................................................................................. 50

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 6 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

16.3. MLX90614xCF ................................................................................................................................. 51

16.4. MLX90614xCH ................................................................................................................................. 51

16.5. MLX90614xCI .................................................................................................................................. 52

16.6. MLX90614xCK ................................................................................................................................. 52

16.7. Part marking .................................................................................................................................... 53

16.8. Operating and storage humidity range ......................................................................................... 53

17. Table of figures

17. Table of figures17. Table of figures

17. Table of figures

................................

................................................................

..................................

....

..

54

5454

54

18. References

18. References18. References

18. References................................

................................................................

.........................................

..................

.........

55

5555

55

19. Contact

19. Contact19. Contact

19. Contact

................................

................................................................

..............................................

............................

..............

56

5656

56

20. Disclaimer

20. Disclaimer20. Disclaimer

20. Disclaimer

................................

................................................................

..........................................

....................

..........

56

5656

56

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 7 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

4. Glossary of Terms

PTAT

P

roportional

T

o

A

bsolute

T

emperature sensor (package temperature)

POR

P

ower

O

n

R

eset

HFO

H

igh

F

requency

O

scillator (RC type)

DSP

D

igital

S

ignal

P

rocessing

FIR

F

inite

I

mpulse

R

esponse. Digital filter

IIR

I

nfinite

I

mpulse

R

esponse. Digital filter

IR

I

nfra

-

R

ed

PWM

P

ulse

W

ith

M

odulation

DC

D

uty

C

ycle (of the PWM) ;

D

irect

C

urrent (for settled conditions specifications)

FOV

F

ield

O

f

V

iew

SDA,SCL

S

erial

DA

ta,

S

e

rial

CL

ock

–

SMBus compatible communication pins

Ta

A

mbient

T

emperature measured from the chip

–

(the package temperature)

To

O

bject

T

emperature, ‘seen’ from IR sensor

ESD

E

lectro

-

S

tatic

D

ischarge

EMC

E

lectro

-

M

agnetic

C

ompatibility

ASSP

A

pplication

S

pecific

S

tandard

P

roduct

TBD

T

o

B

e

D

efined

Note: sometimes the MLX90614xxx is referred as “the module”.

5. Maximum ratings

Parameter MLX90614ESF-Axx

MLX90614ESF-Bxx

MLX90614ESF-Dxx

MLX90614KSF-Axx

Supply Voltage, V

DD

(over voltage) 7V 5V 7V

Supply Voltage, V

DD

(operating) 5.5 V 3.6V 5.5V

Reverse Voltage 0.4 V

Operating Temperature Range, T

A

-40°C…+85°C -40°C…+125°C

Storage Temperature Range, T

S

-40°C…+125°C -40°C…+125°C

ESD Sensitivity (AEC Q100 002) 2kV

DC current into SCL / Vz (Vz mode) 2 mA

DC sink current, SDA / PWM pin 25 mA

DC source current, SDA / PWM pin 25 mA

DC clamp current, SDA / PWM pin 25 mA

DC clamp current, SCL pin 25 mA

Table 1: Absolute maximum ratings for MLX90614

Exceeding the absolute maximum ratings may cause permanent damage.

Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 8 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

6. Pin definitions and descriptions

Figure 2: Pin description

Pin Name Function

SCL / Vz

Serial clock input for 2 wire communications protocol. 5.7V zener is available at

this pin for connection of external bipolar transistor to MLX90614Axx to supply

the device from external 8…16V source.

SDA / PWM

Digital input / output. In normal mode the measured object temperature is

available at this pin Pulse Width Modulated.

In SMBus compatible mode the pin is automatically configured as open drain

NMOS.

VDD External supply voltage.

VSS Ground. The metal can is also connected to this pin.

Table 2: Pin description MLX90614

Note:

for +12V (+8…+16V) powered operation refer to the Application information section. For EMC and isothermal

conditions reasons it is highly recommended not to use any electrical connection to the metal can except by the VSS pin.

With the SCL / Vz and PWM / SDA pins operated in 2-wire interface mode, the input Schmidt trigger function is automatically

enabled.

Bottom view

2 - SDA / PWM

4 - VSS

3 - VDD

1 - SCL / Vz

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 9 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

7. Electrical Specifications

7.1.

7.1.7.1.

7.1. MLX90614Axx

MLX90614AxxMLX90614Axx

MLX90614Axx

All parameters are valid for T

A

= 25 ˚C, V

DD

=5V (unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Units

Supplies

External supply V

DD

4.5 5 5.5 V

Supply current I

DD

No load 1.3 2 mA

Supply current

(programming) I

DDpr

No load, erase/write EEPROM

operations 1.5 2.5 mA

Zener voltage Vz Iz = 75…1000μA (Ta=room) 5.5 5.7 5.9 V

Zener voltage Vz(Ta) Iz = 70…1000μA,

full temperature range 5.15 5.7 6.24 V

Power On Reset

POR level V

POR_up

Power-up (full temp range) 1.4 1.75 1.95 V

POR level V

POR_down

Power –down (full temp range) 1.3 1.7 1.9 V

POR hysteresis V

POR_hys

Full temp range 0.08 0.1 1.15 V

V

DD

rise time (10% to 90% of

specified supply voltage)

T

POR

Ensure POR signal 20 ms

Output valid

(result in RAM) Tvalid After POR 0.25 s

Pulse width modulation

1

PWM resolution PWMres Data band 10 bit

PWM output period PWM

T,def

Factory default, internal oscillator

factory calibrated

1.024 ms

PWM period stability dPWM

T

Internal oscillator factory

calibrated, over the entire

operation range and supply voltage

-10 +10 %

Output high Level PWM

HI

I

source

= 2 mA V

DD

-0.2 V

Output low Level PWM

LO

I

sink

= 2 mA V

SS

+0.2 V

Output drive current Idrive

PWM

Vout,H = V

DD

- 0.8V 7 mA

Output sink current Isink

PWM

Vout,L = 0.8V 13.5 mA

Continued on next page

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 10 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Parameter Symbol Test Conditions Min Typ Max Units

SMBus compatible 2-wire interface

2

Input high voltage V

IH

(Ta, V) Over temperature and supply 3 V

Input low voltage V

IL

(Ta, V) Over temperature and supply 0.6 V

Output low voltage V

OL

Over temperature and supply, Isink

= 2mA 0.2 V

SCL leakage I

SCL

, leak V

SCL

=4V, Ta=+85°C 30 μA

SDA leakage I

SDA

, leak V

SDA

=4V, Ta=+85°C 0.3 μA

SCL capacitance C

SCL

10 pF

SDA capacitance C

SDA

10 pF

Slave address SA Factory default 5A hex

Wake up request t

wake

SDA low 33 ms

SMBus Request t

REQ

SCL low 1.44 ms

Timeout, low T

imeout,L

SCL low 27 33 ms

Timeout, high T

imeout,H

SCL high 45 55 μs

Acknowledge setup time Tsuac(MD) 8-th SCL falling edge, Master 1.5 μs

Acknowledge hold time Thdac(MD) 9-th SCL falling edge, Master 1.5 μs

Acknowledge setup time Tsuac(SD) 8-th SCL falling edge, Slave 2.5 μs

Acknowledge hold time Thdac(SD) 9-th SCL falling edge, Slave 1.5 μs

EEPROM

Data retention Ta = +85°C 10 years

Erase/write cycles Ta = +25°C 100,000 Times

Erase/write cycles Ta = +125°C 10,000 Times

Erase cell time Terase 5 ms

Write cell time Twrite 5 ms

Table 3: Electrical specification MLX90614Axx

Notes: All the communication and refresh rate timings are given for the nominal calibrated HFO frequency and will vary

with this frequency’s variations.

1. With large capacitive load lower PWM frequency is recommended. Thermal relay output (when configured) has

the PWM DC specification and can be programmed as push-pull, or NMOS open drain. PWM is free-running, power-up

factory default is SMBus, refer to section 8.6, “Switching between PWM and SMBus communication” for more details.

2. For SMBus compatible interface on 12V application refer to Application information section. SMBus compatible

interface is described in details in the SMBus detailed description section. Maximum number of MLX90614 devices on one bus

is 127, higher pull-up currents are recommended for higher number of devices, faster bus data transfer rates, and increased

reactive loading of the bus.

MLX90614 is always a slave device on the bus. MLX90614 can work in both low-power and high-power SMBus

communication.

All voltages are referred to the Vss (ground) unless otherwise noted.

Sleep mode is not available on the 5V version (MLX90614Axx).

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 11 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

7.2.

7.2.7.2.

7.2. MLX90614Bxx, MLX90614Dxx

MLX90614Bxx, MLX90614DxxMLX90614Bxx, MLX90614Dxx

MLX90614Bxx, MLX90614Dxx

All parameters are valid for T

A

= 25 ˚C, V

DD

=3V (unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Units

Supplies

External supply V

DD

2.6 3 3.6 V

Supply current I

DD

No load 1.3 2 mA

Supply current

(programming) I

DDpr

No load, erase / write EEPROM

operations 1.5 2.5 mA

Sleep mode current Isleep no load 1 2.5 5 μA

Sleep mode current Isleep Full temperature range 1 2.5 6 μA

Power On Reset

POR level V

POR_up

Power-up (full temp range) 1.4 1.75 1.95 V

POR level V

POR_down

Power –down (full temp range) 1.3 1.7 1.9 V

POR hysteresis V

POR_hys

Full temp range 0.08 0.1 1.15 V

V

DD

rise time

(10% to 90% of

specified supply voltage)

T

POR

Ensure POR signal 20 ms

Output valid Tvalid After POR 0.25 s

Pulse width modulation

1

PWM resolution PWMres Data band 10 bit

PWM output period PWM

T,def

Factory default, internal oscillator

factory calibrated 1.024 ms

PWM period stability dPWM

T

Internal oscillator factory

calibrated, over the entire

operation range and supply voltage

-10 +10 %

Output high Level PWM

HI

I

source

= 2 mA V

DD

-0.25 V

Output low Level PWM

LO

I

sink

= 2 mA V

SS

+0.25 V

Output drive current Idrive

PWM

Vout,H = V

DD

- 0.8V 4.5 mA

Output sink current Isink

PWM

Vout,L = 0.8V 11 mA

Continued on next page

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 12 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Parameter Symbol Test Conditions Min Typ Max Units

SMBus compatible 2-wire interface

2

Input high voltage V

IH

(Ta,V) Over temperature and supply VDD-0.1 V

Input low voltage V

IL

(Ta,V) Over temperature and supply 0.6 V

Output low voltage V

OL

Over temperature and supply,

Isink = 2mA 0.25 V

SCL leakage I

SCL

,leak V

SCL

=3V, Ta=+85°C 20 μA

SDA leakage I

SDA

,leak V

SDA

=3V, Ta=+85°C 0.25 μA

SCL capacitance C

SCL

10 pF

SDA capacitance C

SDA

10 pF

Slave address SA Factory default 5A hex

Wake up request t

wake

SDA low 33 ms

SMBus Request t

REQ

SCL low 1.44 ms

Timeout,low T

imeout,L

SCL low 27 33 ms

Timeout, high T

imeout,H

SCL high 45 55 μs

Acknowledge setup time Tsuac(MD) 8-th SCL falling edge, Master 1.5 μs

Acknowledge hold time Thdac(MD) 9-th SCL falling edge, Master 1.5 μs

Acknowledge setup time Tsuac(SD) 8-th SCL falling edge, Slave 2.5 μs

Acknowledge hold time Thdac(SD) 9-th SCL falling edge, Slave 1.5 μs

EEPROM

Data retention Ta = +85°C 10 years

Erase/write cycles Ta = +25°C 100,000 Times

Erase/write cycles Ta = +125°C 10,000 Times

Erase cell time Terase 5 ms

Write cell time Twrite 5 ms

Table 4: Electrical specification MLX90614Bxx, Dxx

Note: refer to MLX90614Axx notes.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 13 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8. Detailed description

8.1.

8.1.8.1.

8.1. Block diagram

Block diagramBlock diagram

Block diagram

Figure 3: Block diagram

8.2.

8.2.8.2.

8.2. Signal processing principle

Signal processing principleSignal processing principle

Signal processing principle

The operation of the MLX90614 is controlled by an internal state machine, which controls the measurements and

calculations of the object and ambient temperatures and does the post-processing of the temperatures to output them

through the PWM output or the SMBus compatible interface.

The ASSP supports 2 IR sensors (second one not implemented in the MLX90614xAx).The output of the IR sensors is

amplified by a low noise low offset chopper amplifier with programmable gain, converted by a Sigma Delta modulator

to a single bit stream and fed to a powerful DSP for further processing. The signal is treated by programmable (by

means of EEPROM contend) FIR and IIR low pass filters for further reduction of the band width of the input signal to

achieve the desired noise performance and refresh rate. The output of the IIR filter is the measurement result and is

available in the internal RAM. 3 different cells are available: One for the on-board temperature sensor and 2 for the IR

sensors.

Based on results of the above measurements, the corresponding ambient temperature Ta and object temperatures To

are calculated. Both calculated temperatures have a resolution of 0.01˚C. The data for Ta and To can be read in two

ways: Reading RAM cells dedicated for this purpose via the 2-wire interface (0.02°C resolution, fixed ranges), or

through the PWM digital output (10 bit resolution, configurable range).

In the last step of the measurement cycle, the measured Ta and To are rescaled to the desired output resolution of the

PWM) and the recalculated data is loaded in the registers of the PWM state machine, which creates a constant

frequency with a duty cycle representing the measured data.

81101

OPA ADC DSP

PWM

STATE MACHINE

t°

Voltage

Regulator

90302

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 14 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.3.

8.3.8.3.

8.3. Block description

Block descriptionBlock description

Block description

8.3.1.

8.3.1.8.3.1.

8.3.1. Amplifier

AmplifierAmplifier

Amplifier

A low noise, low offset amplifier with programmable gain is used for amplifying the IR sensor voltage. By carefully

designing the input modulator and balanced input impedance, the max offset of the system is 0.5μV.

8.3.2.

8.3.2.8.3.2.

8.3.2. Supply regulator and POR

Supply regulator and PORSupply regulator and POR

Supply regulator and POR

The module can operate from 3 different supplies:

VDD = 5V  MLX90614Axx

VDD = 3V  MLX90614Bxx (battery or regulated supply)

VDD = 8V…16V  MLX90614Axx few external components are necessary please refer to “Applications information”

section for information about adopting higher voltage supplies.

The Power On Reset (POR) is connected to Vdd supply. The on-chip POR circuit provides an active (high) level of the POR

signal when the Vdd voltage rises above approximately 0.5V and holds the entire MLX90614 in reset until the Vdd is higher

than the specified POR threshold V

POR

. During the time POR is active, the POR signal is available as an open drain at the

PWM/SDA pin. After the MLX90614 exits the POR condition, the function programmed in EEPROM takes precedence for that

pin.

8.3.3.

8.3.3.8.3.3.

8.3.3. EEPROM

EEPROMEEPROM

EEPROM

A limited number of addresses in the EEPROM memory can be changed by the customer. The whole EEPROM can be read

through the SMBus interface.

EEPROM (32X16)

Name Address Write access

To

max

0x00

Yes

To

min

0x01

Yes

PWMCTRL

0x02

Yes

Ta range

0x03

Yes

Emissivity correction coefficient

0x04

Yes

Config

Register1

0x05

Yes

Melexis reserved

0x06

No

…

Melexis reserved

0x0D

No

SMBus address (LSByte only)

0x0E

Yes

Melexis reserved

0x0F

Yes

Melexis reserved

0x10

No

…

Melexis reserved

0x18

No

Melexis reserved

0x19

Yes

Melexis

reserved

0x1A

No

Melexis reserved

0x1B

No

ID number

0x1C

No

ID number

0x1D

No

ID number

0x1E

No

ID number

0x1F

No

Table 5: EEPROM table

The addresses To

max

, To

min

and Ta range are for customer dependent object and ambient temperature ranges. For details see

section 8.5.3 below in this document

The address Emissivity contains the object emissivity (factory default 1.0 = 0xFFFF), 16 bit.

Emissivity = dec2hex[ round( 65535 x

ε

) ]

Where dec2hex[ round( X ) ] represents decimal to hexadecimal conversion with round-off to nearest value (not truncation).

In this case the physical emissivity values are

ε

= 0.1…1.0.

Erase (write 0) must take place before write of desired data is made.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 15 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

PWM period configuration: Period in extended PWM mode is twice the period in single PWM mode.

In single PWM mode period is T = 1.024*P [ms], where P is the number, written in bits 15…9 PWMCTRL. Maximum period is

then 131.072 ms for single and 262.144 ms for extended. These values are typical and depend on the on-chip RC oscillator

absolute value. The duty cycle must be calculated instead of working only with the high time only in order to avoid errors

from the period absolute value deviations.

The address PWMCTRL consists of control bits for configuring the PWM/SDA pin as follows:

* Values are valid for nominal HFO frequency

Table 6: PWM control bits

The address ConfigRegister1 consists of control bits for configuring the analog and digital parts:

Note: The following bits / registers should not be altered (except with special tools – contact Melexis for such tools

availability) in order to keep the factory calibration relevant:

Ke [15...0]; Config Register1 [14...11;7;3]; addresses 0x0F and 0x19.

Table 7: Configuration register 1

Check www.melexis.com for latest application notes with details on EEPROM settings.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

PWM control bit meaning

0 - PWM extended mode

1 - PWM single mode

0 - PWM mode disabled (EN_PWM)

1 - PWM mode enabled (EN_PWM)

0 - SDA pin configured as Open Drain (PPODB)

1 - SDA pin configured as Push-Pull (PPODB)

0 - PWM mode selected (TRPWMB)

1 - Thermal relay mode selected (TRPWMB)

- PWM repetition number 0…62 step 2

- PWM period 1.024*ms (Single PWM mode) or 2.048*ms (Extendet PWM mode)

multiplied by the number written in this place (128 in case the number is 0)

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Config register bit meaning

1 0 0 - IIR (100%) a1=1, b1=0

1 0 1 - IIR (80%) a1=0.8, b1=0.2

1 1 0 - IIR (67%) a1=0.666, b1=0.333

1 1 1 - IIR (57%) a1=0.571, b1=0.428

0 0 0 - IIR (50%) a1=0.5, b1=0.5

0 0 1 - IIR (25%) a1=0.25, b1=0.75

0 1 0 - IIR (17%) a1=0.166(6), b1=0.83(3)

0 1 1 - IIR (13%) a1=0.125, b1=0.875

0 - Repeat sensor test "OFF"

1 - Repeat sensor test "ON"

0 0 - Ta, Tobj1

0 1 - Ta, Tobj2

1 0 - Tobj2

1 1 - Tobj1, Tobj2

0

- Single IR sensor

1 - Dual IR sensor

0 - Positive sign of Ks

1 - Negative sign of Ks

0 0 0 - FIR = 8 not recommended

0 0 1 - FIR = 16 not recommended

0 1 0 - FIR = 32 not recommended

0 1 1 - FIR = 64 not recommended

1 0 0 - FIR = 128

1 0 1 - FIR = 256

1 1 0 - FIR = 512

1 1 1 - FIR = 1024

0 0 0 - GAIN = 1 - Amplifier is bypassed

0 0 1 - GAIN = 3

0 1 0 - GAIN = 6

0 1 1 - GAIN = 12,5

1 0 0 - GAIN = 25

1 0 1 - GAIN = 50

1 1 0 - GAIN = 100

1 1 1 - GAIN = 100

0 - Positive sign of Kt2

1 - Negative sign of Kt2

0 - Enable sensor test

1 - Disable sensor test

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 16 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

On-chip filtering and settling time:

The MLX90614 features configurable on-chip digital filters. They allow customization for speed or noise. Factory default

configurations and the typical settling time and noise for the MLX90614 family are given below.

Device Settling time, sec Typical noise, °C rms Spike limit

MLX90614AAA, BAA, DAA

0.10

0.05

100%

MLX90614ABA, BBA

0.14

0.07

100%

MLX90614ACC, BCC

, DCC

0.14

0.18

100%

MLX90614

ACF, BCF

1.33

0.10

50%

MLX90614DCH, DCI, BCH, BCI

0.65

0.

10

80%

MLX90614

ACK, BCK

3.23

0.30

25%

Table 8: factory default IIR and FIR configuration, settling time and typical noise

Details on the filters are given in the application note “Understanding MLX90614 on-chip digital signal filters” available from

www.melexis.com.

The evaluation board, EVB90614 supported by PC SW allows easy configuration of the filters, while not requiring in-depth

understanding of the EEPROM.

The available filter settings and the settling times are listed below. Settling time depends on three configurations: single /

dual zone, IIR filter settings and FIR filter settings. The FIR filter has a straight forward effect on noise (4 times decreasing of

filter strength increases the noise 2 times and vice versa). The IIR filter provides an additional, spike limiting feature. Spike

limit defines the level of magnitude to which the spike would be limited – for example, 25% denotes that if a 20°C

temperature delta spike is measured the temperature reading by the MLX90614 will spike only 5°C.

Table 9: possible IIR and FIR settings

Note: Settling time is in seconds and depends on internal oscillator absolute value.

100% spike limit appears with the IIR filter bypassed, and there is no spike limitation.

Settling time (s) Settling time (s)

90614xAx 90614xBx, 90614xCx

xxx 000…011

100 100 0.04 0.06 100.00%

100 101 0.05 0.07 100.00%

100 110 0.06 0.10 100.00%

100 111 0.10 0.14 100.00%

101 100 0.12 0.20 80.00%

101 101 0.16 0.24 80.00%

101 110 0.22 0.34 80.00%

101 111 0.35 0.54 80.00%

110 100 0.24 0.38 66.70%

110 101 0.30 0.48 66.70%

110 110 0.43 0.67 66.70%

110 111 0.70 1.10 66.70%

111 100 0.26 0.42 57.00%

111 101 0.34 0.53 57.00%

111 110 0.48 0.75 57.00%

111 111 0.78 1.20 57.00%

000 100 0.30 0.47 50.00%

000 101 0.37 0.60 50.00%

000 110 0.54 0.84 50.00%

000 111 0.86 1.33 50.00%

001 100 0.70 1.10 25.00%

001 101 0.88 1.40 25.00%

001 110 1.30 2.00 25.00%

001 111 2.00 3.20 25.00%

010 100 1.10 1.80 16.70%

010 101 1.40 2.20 16.70%

010 110 2.00 3.20 16.70%

010 111 3.30 5.00 16.70%

011 100 1.50 2.40 12.50%

011 101 1.90 3.00 12.50%

011 110 2.80 4.30 12.50%

011 111 4.50 7.00 12.50%

Not recommended

FIR settingIIR setting Spike limit

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 17 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.3.4.

8.3.4.8.3.4.

8.3.4. RAM

RAMRAM

RAM

It is not possible to write into the RAM memory. It can only be read and only a limited number of RAM registers are of

interest to the customer.

RAM (32x16)

Name Address Read access

Melexis reserved

0x00

Yes

…

Melexis reserved

0x

0

3

Yes

Raw data IR channel 1

0x

0

4

Raw data IR channel 2

0x0

5

T

A

0x06 Yes

T

OBJ1

0x07 Yes

T

OBJ2

0x08 Yes

Melexis reserved

0x0

9

Yes

…

Melexis

reserved

0x

1F

Yes

Table 10: Ram addresses

8.4.

8.4.8.4.

8.4. SMBus compatible 2

SMBus compatible 2SMBus compatible 2

SMBus compatible 2-

--

-wire protocol

wire protocolwire protocol

wire protocol

The chip supports a 2 wires serial protocol, build with pins PWM / SDA and SCL.

 SCL – digital input only, used as the clock for SMBus compatible communication. This pin has the auxiliary

function for building an external voltage regulator. When the external voltage regulator is used, the 2-wire

protocol is available only if the power supply regulator is overdriven.

 PWM/SDA – Digital input / output, used for both the PWM output of the measured object temperature(s) or

the digital input / output for the SMBus. In PWM mode the pin can be programmed in EEPROM to operate as

Push / Pull or open drain NMOS (open drain NMOS is factory default). In SMBus mode SDA is forced to open

drain NMOS I/O, push-pull selection bit defines PWM / Thermal relay operation.

SMBus communication with MLX90614 is covered in details in application notes, available from www.melexis.com.

8.4.1.

8.4.1.8.4.1.

8.4.1. Functional description

Functional descriptionFunctional description

Functional description

The SMBus interface is a 2-wire protocol, allowing communication between the Master Device (MD) and one or more Slave

Devices (SD). In the system only one master can be presented at any given time [1]. The MLX90614 can only be used as a

slave device.

Generally, the MD initiates the start of data transfer by selecting a SD through the Slave Address (SA).

The MD has read access to the RAM and EEPROM and write access to 9 EEPROM cells (at addresses 0x00, 0x01, 0x02, 0x03,

0x04, 0x05*, 0x0E, 0x0F, 0x19). If the access to the MLX90614 is a read operation it will respond with 16 data bits and 8 bit

PEC only if its own slave address, programmed in internal EEPROM, is equal to the SA, sent by the master. The SA feature

allows connecting up to 127 devices (SA=0x00…0x07F) with only 2 wires, unless the system has some of the specific features

described in paragraph 5.2 of reference [1]. In order to provide access to any device or to assign an address to a SD before it

is connected to the bus system, the communication must start with zero SA followed by low R/W

¯

bit. When this command is

sent from the MD, the MLX90614 will always respond and will ignore the internal chip code information.

Special care must be taken not to put two MLX90614 devices with the same SA on the same bus as MLX90614 does not

support ARP [1].

The MD can force the MLX90614 into low consumption mode “sleep mode” (3V version only).

Read flags like “EEBUSY” (1 – EEPROM is busy with executing the previous write/erase), “EE_DEAD” (1 – there is fatal

EEPROM error and this chip is not functional**).

Note*: This address is readable and writable. Bit 3 should not be altered as this will cancel the factory calibration.

Note**: EEPROM error signaling is implemented in automotive grade parts only.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 18 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.4.2.

8.4.2.8.4.2.

8.4.2. Differences with the standard SMBus specification (reference [1])

Differences with the standard SMBus specification (reference [1])Differences with the standard SMBus specification (reference [1])

Differences with the standard SMBus specification (reference [1])

There are eleven command protocols for standard SMBus interface. The MLX90614 supports only two of them. Not

supported commands are:

 Quick Command

 Byte commands - Sent Byte, Receive Byte, Write Byte and Read Byte

 Process Call



Block commands

– Block Write and Write-Block Read Process Call

Supported commands are:

 Read Word

 Write Word

8.4.3.

8.4.3.8.4.3.

8.4.3. Detailed description

Detailed descriptionDetailed description

Detailed description

The PWM / SDA pin of MLX90614 can operate also as PWM output, depending on the EEPROM settings. If PWM is enabled,

after POR the PWM / SDA pin is directly configured as PWM output. Even if the device is in PWM mode SMBus

communication may be restored by a special command. That is why hereafter both modes are treated separately.

8.4.3.1.

8.4.3.1.8.4.3.1.

8.4.3.1. Bus Protocol

Bus ProtocolBus Protocol

Bus Protocol

Figure 4: SMBus packet element key

After every received 8 bits the SD should issue ACK or NACK. When a MD initiates communication, it first sends the address

of the slave and only the SD which recognizes the address will ACK, the rest will remain silent. In case the SD NACKs one of

the bytes, the MD should stop the communication and repeat the message. A NACK could be received after the PEC. This

means that there is an error in the received message and the MD should try sending the message again. The PEC calculation

includes all bits except the START, REPEATED START, STOP, ACK, and NACK bits. The PEC is a CRC-8 with polynomial

X8+X2+X1+1. The Most Significant Bit of every byte is transferred first.

SWrSlave Address A Data Byte

A

P

S

Start Condition

Sr

Repeated Start Condition

Rd

Read (bit value of 1)

Wr

Write (bit value of 0)

A

Acknowledge (this bit can be 0 for ACK and 1 for NACK)

S

Stop Condition

PEC

Packet Error Code

Master

-

to

-

Slave

-

to

-

Master

1

7

1

8

1

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 19 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.4.3.1.1.

8.4.3.1.1.8.4.3.1.1.

8.4.3.1.1. Read Word (depending on the command

Read Word (depending on the command Read Word (depending on the command

Read Word (depending on the command –

––

–

RAM or EEPROM)

RAM or EEPROM)RAM or EEPROM)

RAM or EEPROM)

Figure 5: SMBus read word format

8.4.3.1.2.

8.4.3.1.2.8.4.3.1.2.

8.4.3.1.2. Write Word (depending on the command

Write Word (depending on the command Write Word (depending on the command

Write Word (depending on the command –

––

–

RAM or EEPROM)

RAM or EEPROM)RAM or EEPROM)

RAM or EEPROM)

Figure 6: SMBus write word format

8.4.4.

8.4.4.8.4.4.

8.4.4. Bit transfer

Bit transferBit transfer

Bit transfer

Figure 7: Recommended timing on SMBus

The data on PWM / SDA must be changed when SCL is low (min 300ns after the falling edge of SCL). The data is fetched by

both MD and SDs on the rising edge of the SCL. The recommended timing for changing data is in the middle of the period

when the SCL is low.

SCL

Sampling data

SDA

Changing data

S

Wr

Slave Address

A

Data Byte Low

A

P

Command

A

Sr

Slave Address

Rd

1 7 1 1

8 1 1

7 1

8 1 1

………..

A

1

Data Byte High

A

8

1

PEC

A

8 1

S

Wr

Slave Address

A

Data Byte Low

A

P

Command

A

1

7

1

8

1

8

1

………..

Data Byte High

A

8

1

PEC

A

8

1

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 20 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.4.5.

8.4.5.8.4.5.

8.4.5. Commands

CommandsCommands

Commands

RAM and EEPROM can be read both with 32x16 sizes. If the RAM is read, the data are divided by two, due to a sign bit in

RAM (for example, T

O1

- RAM address 0x07 will sweep between 0x27AD to 0x7FFF as the object temperature changes from -

70.01°C…+382.19°C). The MSB read from RAM is an error flag (active high) for the linearized temperatures (T

O1

,

T

O2

and T

a

).

The MSB for the raw data (e.g. IR sensor1 data) is a sign bit (sign and magnitude format). A write of 0x0000 must be done

prior to writing in EEPROM in order to erase the EEPROM cell content. Refer to EEPROM detailed description for factory

calibration EEPROM locations that need to be kept unaltered.

Opcode

Command

000x

xxxx*

RAM Access

001x xxxx*

EEPROM Access

1111_0000**

Read Flags

1111_1111

Enter SLEEP mode

Table 11: SMBus commands

Note*: The xxxxx represent the 5 LSBits of the memory map address to be read / written.

Note**: Behaves like read command. The MLX90614 returns PEC after 16 bits data of which only 4 are meaningful and if the

MD wants it, it can stop the communication after the first byte. The difference between read and read flags is that the latter

does not have a repeated start bit.

Flags read are:

Data[7] - EEBUSY - the previous write/erase EEPROM access is still in progress. High active.

Data[6] - Unused

Data[5] - EE_DEAD - EEPROM double error has occurred. High active.

Data[4] - INIT - POR initialization routine is still ongoing. Low active.

Data[3] - Not implemented.

Data[2...0] and Data[8...15] - All zeros.

Flag read is a diagnostic feature. The MLX90614 can be used regardless of these flags.

For details and examples for SMBus communication with the MLX90614 check the www.melexis.com

8.4.6.

8.4.6.8.4.6.

8.4.6. SMBus communication examples

SMBus communication examplesSMBus communication examples

SMBus communication examples

Figure 8: Read word format (SA=0x5A, read RAM=0x07, result=0x3AD2, PEC=0x30)

Figure 9: Write word format (SA=0x5A, write EEPROM=0x02, data=0xC807, PEC=0x48)

SCL

SDA

1 0 1 1 0 1 0 0A 0 0 0 0 1 1 1 AS S 0 1 1 0 1 0 A1 A A P

SA_W = 0xB4 Command = 0x07

RW 1 0 1 0 0 11 0 0 1 1 1 0 10 0 0 1 1 0 0 00 0 A

LSByte = 0xD2 MSByte = 0x3A PEC = 0x30SA_R = 0xB5

SCL

SDA

1 0 1 1 0 1 0 0A 0 1 0 0 0 1 0 AS 0 0 0 0 1 1 A0 A A P

Command = 0x22

1W 1 0 0 1 0 01 0 1 0 0 1 0 00 0

MSByte = 0xC8 PEC = 0x48LSByte = 0x07

SA_W = 0xB4

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 21 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.4.7.

8.4.7.8.4.7.

8.4.7. Timing specification

Timing specificationTiming specification

Timing specification

The MLX90614 meets all the timing specifications of the SMBus [1]. The maximum frequency of the MLX90614 SMBus is 100

KHz and the minimum is 10 KHz.

The specific timings in MLX90614’s SMBus are:

SMBus Request (t

REQ

) is the time that the SCL should be forced low in order to switch MLX90614 from PWM mode to SMBus

mode – at least 1.44ms;

Timeout L is the maximum allowed time for SCL to be low during communication. After this time the MLX90614 will reset its

communication block and will be ready for new communication – not more than 27ms;

Timeout H is the maximum allowed time for SCL to be high during communication.

After this time MLX90614 will reset its

communication block assuming that the bus is idle (according to the SMBus specification) – not more than 45μs.

Tsuac(SD) is the time after the eighth falling edge of SCL that MLX90614 will force PWM / SDA low to acknowledge the last

received byte – not more than 2.5μs.

Thdac(SD) is the time after the ninth falling edge of SCL that MLX90614 will release the PWM / SDA (so the MD can continue

with the communication) – not more than 1.5μs.

Tsuac(MD) is the time after the eighth falling edge of SCL that MLX90614 will release PWM / SDA (so that the MD can

acknowledge the last received byte) – not more than 1,5μs.

Thdac(MD) is the time after the ninth falling edge of SCL that MLX90614 will take control of the PWM / SDA (so it can

continue with the next byte to transmit) – not more than 1.5μs.

The indexes MD and SD for the latest timings are used – MD when the master device is making acknowledge; SD when the

slave device is making acknowledge. For other timings see [1].

Figure 10: SMBus timing specification and definition

SCL

SDA

Timeout_L

> 27ms

Timeout_H

> 45µs

1 2 3 4 5 6 7 8 9

1 0 1 0 1 0 1 1 ACK

Tsuac Thdac

MD < 1.5µs

SD < 2.5µs

MD < 1.5µs

SD < 1.5µs

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 22 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.4.8.

8.4.8.8.4.8.

8.4.8. Sleep Mode

Sleep ModeSleep Mode

Sleep Mode

The MLX90614 can enter in Sleep Mode via the command “Enter SLEEP mode” sent via the SMBus interface. This mode is

not available for the 5V supply version. There are two ways to put MLX90614 into power-up default mode:

- POR

- By Wake up request  SCL pin high and then PWM/SDA pin low for at least t

DDQ

> 33ms

If EEPROM is configured for PWM (EN_PWM is high), the PWM interface will be selected after awakening and if PWM

control [2], PPODB is 1 the MLX90614 will output a PWM pulse train with push-pull output.

NOTE: In order to limit the current consumption to the typical 2.5μA Melexis recommends that the SCL pin is kept low during

sleep as there is leakage current trough the internal synthesized zener diode connected to SCL pin. This may be achieved by

configuring the MD driver of SCL pin as Push-Pull and not having Pull-Up resistor connected on SCL line.

8.4.8.1.

8.4.8.1.8.4.8.1.

8.4.8.1. Enter Sleep Mode

Enter Sleep ModeEnter Sleep Mode

Enter Sleep Mode

Figure 11: Enter sleep mode command (SA = 0x5A, Command = 0xFF, PEC = 0xE8)

8.4.8.2.

8.4.8.2.8.4.8.2.

8.4.8.2. Exit from Sleep Mode (Wake up request)

Exit from Sleep Mode (Wake up request)Exit from Sleep Mode (Wake up request)

Exit from Sleep Mode (Wake up request)

Figure 12: Exit Sleep Mode

After wake up the first data is available after 0.25 seconds (typ). On-chip IIR filter is skipped for the very first measurement.

All measurements afterwards pass the embedded digital filtering as configured in EEPROM. Details on embedded filtering

are available in application note “Understanding MLX90614 on-chip digital signal filters”, available from www.melexis.com

SCL

SDA

1 0 1 1 0 1 0 1A 1 1 1 1 1 1 1 AS 1 1 0 1 0 0 A1 P

Command = 0xFF

0W

PEC = 0xE8

SA_W = 0xB4

Normal operation mode Sleep mode

SDA

SCL > 33ms

Sleep mode Normal mode

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 23 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.4.9.

8.4.9.8.4.9.

8.4.9. MLX90614 SMBus specific remarks

MLX90614 SMBus specific remarksMLX90614 SMBus specific remarks

MLX90614 SMBus specific remarks

The auxiliary functions of the SCL pin (zener diode) add undershoot to the clock pulse (5V devices only) as shown in the

picture below (see Figure 13). This undershoot is caused by the transient response of the on-chip synthesized Zener diode.

Typical duration of undershoot is approximately 15μs. An increased reactance of the SCL line is likely to increase this effect.

Undershoot does not affect the recognition of the SCL rising edge by the MLX90914, but may affect proper operation of non-

MLX90614 slaves on the same bus.

Figure 13: Undershoot of SCL line due to on chip synthesized Zener diode (5V versions only)

Continuous SMBus readings can introduce and error. As the SCL line inside TO39 package is passing relatively close to the

sensor input and error signal is induced to the sensor output. The manifestation of the problem is wrong temperature

readings. This is especially valid for narrow FOV devices. Possible solution is to keep SDA and SCL line quiet for period longer

than refresh rate and settling time defined by internal settings of MLX90614 prior reading the temperature or switch to

PWM signal and completely disconnect from SDA and SCL line.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 24 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.5.

8.5.8.5.

8.5. PWM

PWMPWM

PWM

The MLX90614 can be read via PWM or SMBus compatible interface. Selection of PWM output is done in EEPROM

configuration (factory default is SMBus). PWM output has two programmable formats, single and dual data transmission,

providing single wire reading of two temperatures (dual zone object or object and ambient). The PWM period is derived

from the on-chip oscillator and is programmable.

Config Register[5:4] PWM1 data PWM2 data Tmin,1 Tmax,1 Tmin,2 Tmax,2

00 T

A

T

O

1

T

A_r

ange

,L T

A_r

ange

,H T

O

_MIN

T

O_MAX

01 T

A

T

O

2

T

A_ra

nge

,L T

A_r

ange

,H T

O

_MIN

T

O_MAX

11 T

O

1

T

O

2

T

O

_MIN

T

O

_MAX

T

O

_MIN

T

O_MAX

10*

T

O2

Undefined

T

O_MIN

T

O_MAX

N.A.

Table 12: PWM configuration table

Note: Serial data functions (2-wire / PWM) are multiplexed with a thermal relay function (described in the “Thermal

relay” section).

* Not recommended for extended PWM format operation

Figure 14: PWM timing single (above) and extended PWM (bellow)

PWM type t1 t2 t3 t4 t5 t6 t7 t8

Single 1/8 – high 4/8 - var 2/8 1/8 – low NA NA NA NA

Extended - S1 1/16 - high 4/16 - var 2/16 1/16 - low 1/16 - low 4/16 – low 2/16 - low 1/16 - low

Extended - S2 1/16 - high 4/16 - high 2/16 - high 1/16 - high 1/16 - high 4/16 - var 2/16 1/16 - low

Table 13: PWM timing

t1 t2

t3

t4

FE

Valid data band

Error band

Start Stop

0T

5

8

T

1

8T

13

16 T

7

8T

t1 t2

t3

t4

FE

Sensor 1

Error band

Start Stop

0T

1

16 TT

5

16 T

7

16 T

8

16

Valid data band

t5 t6

Sensor 1

t7

FE

Error band

Sensor 2

Valid data band

t8

T

9

16 T

13

16 T

15

16

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 25 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.5.1.

8.5.1.8.5.1.

8.5.1. Single PWM format

Single PWM formatSingle PWM format

Single PWM format

In single PWM output mode the settings for PWM1 data only are used. The temperature reading can be calculated from the

signal timing as:

( )

MINOMINOMAXOOUT

TTT

T

t

T

___

2

2+











−×=

where Tmin and Tmax are the corresponding rescale coefficients in EEPROM for the selected temperature output (Ta, object

temperature range is valid for both Tobj1 and Tobj2 as specified in the previous table) and T is the PWM period. Tout is T

O1

,

T

O2

or T

a

according to Config Register [5:4] settings.

The different time intervals t

1

…t

4

have following meaning:

t

1

: Start buffer. During this time the signal is always high. t

1

= 0.125s x T (where T is the PWM period, please refer to

Figure 14).

t

2

: Valid Data Output Band, 0…1/2T. PWM output data resolution is 10 bit.

t

3

: Error band – information for fatal error in EEPROM (double error detected, not correctable).

t

3

= 0.25s x T. Therefore a PWM pulse train with a duty cycle of 0.875 will indicate a fatal error in EEPROM (for single PWM

format). FE means Fatal Error.

Example:

Figure 15: PWM example single mode

CT

MINO

°= 0

_



( )

3602731515.273100010,

__

ABxdTxEEPROMT

MINOMINO

==+×=

CT

MAXO

°= 50

_



( )

BExdTxEEPROMT

MAXOMAXO

3703231515.273100000,

__

==+×=

Captured PWM period is T = 1004μs

Captured high duration is t = 392 μs

Calculated duty cycle is:

3904.0

1004

392 === T

t

D

or

%04.39

The temperature is calculated as follows:

( ) ( )

CT

O

°=××=+−×−×= 54.26502654.020050125.03904.02

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 26 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.5.2.

8.5.2.8.5.2.

8.5.2. Extended PWM format

Extended PWM formatExtended PWM format

Extended PWM format

The PWM format for extended PWM is shown in Figure 16. Note that with bits DUAL[5:1]>0x00 each period will be

outputted 2N+1 times, where N is the decimal value of the number written in DUAL[5:1] (DUAL[5:1] =PWM control &

clock [8:4] ), like shown on Figure 16.

Figure 16: Extended PWM format with DUAL [5:1] = 01h (2 repetitions for each data)

The temperature transmitted in Data 1 field can be calculated using the following equation:

( )

111

2

1

4

MINMINMAXOUT

TTT

T

t

T+











−×=

For Data 2 field the equation is:

( )

222

5

2

4

MINMINMAXOUT

TTT

T

t

T+











−×=

Time bands are: t

1

=0.0625 x T (Start1), t

3

=0.125 x T and t

4

=0.5625 x T (Start2 = Start1 + Valida_data1 + error_band1 + stop1 +

start2). As shown in Figure 13, in extended PWM format the period is twice the period for the single PWM format. All

equations provided herein are given for the single PWM period T. The EEPROM Error band signaling will be 43.75% duty

cycle for Data1 and 93.75% for Data2.

Note: EEPROM error signaling is implemented in automotive grade parts only.

Figure 17: Example: Extended PWM mode readings – sensor 1 above and sensor 2 bellow

t3

t1 t2

Start

0

T

1

16 T

T

8

16 T

15

16

t=16.875ms

T=100ms (PWM = 10Hz)

t1 t2

Start

0

T

1

16 TT

8

16 T

15

16

t=73.125ms

T=100ms (PWM = 10Hz)

Extended PWM mode sensor 1

Extended PWM mode sensor 2

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 27 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Example: (see Figure 17 above):

Configuration:

Sensor1 = Ta, Sensor2 = T

obj1

 Config Reg[5:4] = 00b,

CT

MINA

°= 0

_



( )

Cxd

T

EEPROMT

A

LRANGEA

30606875.59

64

2.38

100

min_

__

=≈=

+

×=

CT MAXA °= 60

_



( )

9901534375.153

64

2.38

100

max_

__

xd

T

EEPROMT

A

HRANGEA

=≈=

+

×=

( )

{ }

CxTTxEEPROMT LRANGEAHRANGEARANGEA 9930:030, _____ ==

CT MINO °= 0

_



( )

3602731515.273100010, min__ ABxdTxEEPROMT OMINO ==+×=

CT MAXO °= 50

_



( )

BExdTxEEPROMT OMAXO 3703231515.273100000, min__ ==+×=

Captured high durations are:

Sensor 1 – t = 16.875ms at period T = 100ms thus the duty cycle is

16875.0

100

875.16

1

==

S

Duty

Sensor 2 – t = 73.125ms at period T = 100ms thus the duty cycle is

73125.0

100

125.73

2

==

S

Duty

The temperatures are calculated as follows:

( )

MINAMINAMAXASA

TTTStartDutyT

___1

14 +−×−×=

( ) ( )

CT

A

°=+−×−×= 5.2500600625.016875.04

( )

MINOMINOMAXOSO

TTTStartDutyT

___21

24 +−×−×=

( ) ( )

CT

O

°=+−×−×= 75.3300505625.073125.04

1

8.5.3.

8.5.3.8.5.3.

8.5.3. Customizing the temperature range for PWM output

Customizing the temperature range for PWM outputCustomizing the temperature range for PWM output

Customizing the temperature range for PWM output

The calculated ambient and object temperatures are stored in RAM with a resolution of 0.01°C (16 bit). The PWM operates

with a 10-bit word so the transmitted temperature is rescaled in order to fit in the desired range.

For this goal 2 cells in EEPROM are foreseen to store the desired range for To (To

min

and To

max

) and one for Ta (Ta

range

: the

8MSB are foreseen for Ta

max

and the 8LSB for Ta

min

).

Thus the output range for To can be programmed with an accuracy of 0.01°C, while the corresponding Ta range can be

programmed with an accuracy of 0.64°C.

The object data for PWM is rescaled according to the following equation:

1023

,EEPROMEEPROMEEPROM

obj

MINMAX

obj

PWM

obj

PWM

MINRAM

PWM

TT

K

TT

T−

=

−

=

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 28 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

The T

RAM

is the linearized Tobj, 16-bit (0x0000…0xFFFF, 0x0000 for -273.15°C and 0xFFFF for +382.2°C) and the result is a 10-

bit word, in which 0x000 corresponds to To

MIN ,

°C, 0x3FF corresponds to To

MAX

,°C and 1LSB corresponds to

1023

MINMAX

ToTo −

,°C.

100×=

MINMIN

TT

EEPORM

LSB

100×=

MAXMAX

TT

EEPORM

LSB

The ambient data for PWM is rescaled according to the following equation:

ambient

EEPROM

ambient

PWM

MINRAM

PWM

K

TT

T

−

=

Where:

1023

EEPROMEEPROM

MINMAX

ambient

PWM

TT

K−

=

The result is a 10-bit word, where 0x000 corresponds to -38.2°C (lowest Ta that can be read via PWM), 0x3FF corresponds to

125°C (highest Ta that can be read via PWM) and 1LSB corresponds to:

[ ]

C

TT

LSB

MINMAX

°

−

=,

1023

1

( )( )

64

100

2.38 ×−−=

MINMIN

TT EEPORM

LSB

( )( )

64

100

2.38 ×−−=

MAXMAX

TT EEPORM

LSB

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 29 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.6.

8.6.8.6.

8.6. Switching Between PWM / Thermal relay and SMBus communication

Switching Between PWM / Thermal relay and SMBus communicationSwitching Between PWM / Thermal relay and SMBus communication

Switching Between PWM / Thermal relay and SMBus communication

8.6.1.

8.6.1.8.6.1.

8.6.1. PWM is enabled

PWM is enabledPWM is enabled

PWM is enabled

The diagram below illustrates the way of switching to SMBus if PWM / Thermal Relay is enabled (factory programmed POR

default for MLX90614 is SMBus, PWM disabled). Note that the SCL pin needs to be kept high in order to use PWM.

Figure 18: Switching from PWM mode to SMBus

8.6.2.

8.6.2.8.6.2.

8.6.2. Request condition

Request conditionRequest condition

Request condition

Figure 19: Request (switch to SMBus) condition

If PWM / Thermal relay is enabled, the MLX90614’s SMBus Request condition is needed to disable PWM / Thermal relay and

reconfigure PWM/SDA pin before starting SMBus communication. Once PWM / Thermal relay is disabled, it can be only

enabled by switching the supply OFF – ON or exit from Sleep Mode. The MLX90614’s SMBus request condition requires

forcing LOW the SCL pin for period longer than the request time (t

REQ

>1,44ms). The SDA line value is ignored and is

irrelevant in this case.

8.6.3.

8.6.3.8.6.3.

8.6.3. PWM is disabled

PWM is disabledPWM is disabled

PWM is disabled

If PWM is disabled by means of EEPROM the PWM / SDA pin is directly used for the SMBus after POR. Request condition

should not be sent in this case.

SCL

PWM/SDA

Start Stop

t

REQ

PWM mode SMBus mode

>1.44ms

SCL

SMBus Request

t

REQ

>1,44ms

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 30 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.7.

8.7.8.7.

8.7. Computation of ambient and object temperatures

Computation of ambient and object temperaturesComputation of ambient and object temperatures

Computation of ambient and object temperatures

The IR sensor consists of serial connected thermo-couples with cold junctions placed at thick chip substrate and hot

junctions, placed over thin membrane. The IR radiation absorbed from the membrane heats (or cools) it. The thermopile

output signal is:

( )

44

,TaToAToTaV

ir

−×=

Where To is the absolute object temperature (Kelvin), Ta is the sensor die absolute (Kelvin) temperature, and A is the overall

sensitivity.

An on board temperature sensor is needed to measure the chip temperature. After measurement of the output of both

sensors, the corresponding ambient and object temperatures can be calculated. These calculations are done by the internal

DSP, which produces digital outputs, linearly proportional to measured temperatures.

8.7.1.

8.7.1.8.7.1.

8.7.1. Ambient temperature Ta

Ambient temperature TaAmbient temperature Ta

Ambient temperature Ta

The Sensor die temperature is measured with a PTAT element. All the sensors conditioning and data processing is handled

on-chip and the linearized sensor die temperature Ta is available in memory.

The resolution of the calculated temperature is 0.02°C. The sensor is factory calibrated for the full automotive

range -40…+125°C. The linearized die temperature is available in RAM cell 0x06:

0x06=0x2DE4 (11748d) corresponds to -38.2°C (linearization output lower limit)

0x06=0x4DC4 (19908d) corresponds to +125°C. (linearization output higher limit)

The conversions from RAM contend to real Ta is easy using the following relation:

02.0][ ×=° TaregKTa

, or 0.02°K / LSB.

8.7.2.

8.7.2.8.7.2.

8.7.2. Object temperature To

Object temperature ToObject temperature To

Object temperature To

The result has a resolution of 0.02°C and is available in RAM. To is derived from RAM as:

02.0][ ×=° ToregKTo

, or 0.02°K / LSB.

Please note that 1LSB corresponds to 0.02°C and the MSB bit is error flag (if “1” then error).

Example:

1. 0x27AD  -70.00˚C (no error)

2. 0x27AE  -69.98˚C (no error)

3. 0x3AF7  28.75˚C (no error)

4. 0x3AF8  28.77˚C (no error)

5. 0x7FFF  382.19˚C (no error) - maximum possible value returned by MLX90614

6. 0x8XXX  xxx.xx˚C (flag error)

The result is calculated by following expressions (valid for both To and Ta):

1. Convert it to decimal value i.e. 0x3AF7 = 15095d

2. Divide by 50 (or multiply by 0.02) i.e.

9.301

50

15095 =

K (result is in Kelvin)

3. Convert K -> °C i.e. 301.9 - 273.15 = 28.75°C

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 31 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

8.7.3.

8.7.3.8.7.3.

8.7.3. Calculation flow

Calculation flowCalculation flow

Calculation flow

The measurement, calculation and linearization are held by core, which executes a program form ROM.

After POR the chip is initialized with calibration data from EEPROM. During this phase the number of IR sensors is selected

and it is decided which temperature sensor will be used. Measurements, compensation and linearization routines run in a

closed loop afterwards.

Processing ambient temperature includes:

Offset measurement with fixed length FIR filter

Additional filtering with fixed length IIR filter. The result is stored into RAM as T

OS

Temperature sensor measurement using programmable length FIR *.

Offset compensation

Additional processing with programmable length IIR **. The result is stored into RAM as T

D

.

Calculation of the ambient temperature. The result is stored into RAM address 0x06 as T

A

Processing of the object temperature consists of three parts.

The first one is common for both IR sensors, the third part can be skipped if only one IR sensor is used.

IR offset:

Offset measurement with a fixed length FIR

Additional filtering with a fixed length IIR. The result is stored into RAM as IR

OS

.

Gain measurement with fixed length FIR filter

Offset compensation

Additional gain filtering with fixed length IIR, storing the result into RAM as IR

G

.

Gain compensation calculation, the result is stored into RAM as K

G

Object temperature:

IR1 sensor:

IR sensor measurement with programmable length FIR filter *.

Offset compensation

Gain compensation

Filtering with programmable length IIR filter**, storing the result into RAM address 0x04 as IR1

D

.

Calculation of the object temperature. The result is available in RAM address 0x07 as T

O1

.

IR2 sensor:

IR sensor measurement with programmable length FIR filter *.

Offset compensation

Gain compensation

Filtering with programmable length IIR filter**, storing the result into RAM address 0x05 as IR2

D

Calculation of the object temperature. The result is available in RAM address 0x08 as T

O2

PWM calculation:

Recalculate the data for PWM with 10 bit resolution

Load data into PWM module

Note*: The measurements with programmable filter length for FIR filter use the same EEPROM cells for N.

Note**: The IIR filter with programmable filter length uses the same EEPROM cells for L.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 32 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Figure 20: Software flow

8.8.

8.8.8.8.

8.8. Thermal relay

Thermal relayThermal relay

Thermal relay

The MLX90614 can be configured as a thermo relay with programmable threshold and hysteresis on the PWM/SDA pin. The

input for the comparator unit of the relay is the object temperature from sensor 1

The output of the MLX90614 is NOT a relay driver but a logical output which should be connected to a relay driver if

necessary.

The output driver is one and the same for PWM and Thermal relay.

In order to configure the MLX90614 to work as thermal relay two conditions must be met:

o Set bit TRPWMB high at address 0x02 in EEPROM

o Enable PWM output i.e. EN_PWM is set high

The PWM / SDA pin can be programmed as a push-pull or open drain NMOS (via bit PPODB in EEPROM PWMCTRL), which

can trigger an external device. The temperature threshold data is determined by EEPROM at address 0x21 (To

min

) and the

hysteresis at address 0x020 (To

max

).

The logical state of the PWM/SDA pin is as follows:

PWM / SDA pin is high if

hysteresisthresholdT

O

+≥

1

PWM / SDA pin is low if

hysteresisthresholdT

O

−≤

1

Figure 21: Thermal relay: “PWM” pin versus Tobj

Initialization

T

A

Offset meas

OS

Ta

= meas(N

Tos

)

filtering

T

OS

= IIR(L

Tos

,OS

Ta

)

T

A

meas

T

DATA

= meas(N

Ta

)

Offset comp

T

DATAcomp

= T

DATA

-T

OS

filtering

T

D

= IIR(L

Ta

,T

DATAcomp

)

T

A

calculation

T

A

IR Offset meas

OS

IR

= meas(N

IRos

)

filtering

IR

OS

= IIR(L

IRos

,OS

IR

)

IR1 meas

IR1

D

= meas(N

IR

)

Offset comp

IR1

Dcomp

= IR1

D

- IR

OS

filtering

IR1

D

= IIR(L

IR

,IR1

Dg

)

T

OBJ1

calculation

Gain drift

IR

Gm

= meas(N

IRg

)

Offset comp

IR

Gcomp

= IR

Gm

- IR

OS

filtering

IR

G

= IIR(L

G

,IR

Gcomp

)

K

G

calculation

IR offset

Gain comp

IR1

Dg

= IR1

Dcomp

*K

G

IR2 meas

IR2

D

= meas(N

IR

)

Offset comp

IR2

Dcomp

= IR2

D

- IR

OS

filtering

IR2

D

= IIR(L

IR

,IR2

Dg

)

T

OBJ2

calculation

Gain comp

IR2

Dg

= IR2

Dcomp

*K

G

T

OBJ1

T

OBJ2

PWM

calculation

Load PWM

registers

1

123

23

threshold

hysteresis hysteresis

T

“0”

“1”

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 33 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

The MLX90614 preserves its normal operation when configured as a thermal relay (PWM configuration and specification

applies as a general rule also for the thermal relay) and therefore it can be read using the SMBus (entering the SMBus mode

from both PWM and thermal relay configuration is the same).

For example, the MLX90614 can generate a wake-up alert for a system upon reaching a certain temperature and then be

read as a thermometer. Reset conditions (enter and exit Sleep, for example) will be needed in order to return to the thermal

relay configuration.

Example:

CThreshold °= 5



( ) ( )

7602781515.273100010, CAxdThresholdxEEPROM ==+×=

CHysteresis °= 1



( )

00640100100000, xdHysteresisxEEPROM ==×=

Smallest possible hysteresis is 0,01°C or (EEPROM, 0x00 = 0x0001)

PWM / SDA pin will be set low at object temperature below 4°C

PWM / SDA pin will be set high at object temperature higher that 6°C

9. Unique Features

 The MLX90614 is a ready-to use low-cost non-contact thermometer provided from Melexis with output data

linearly dependent on the object temperature with high accuracy and extended resolution.

 The high thermal stability of the MLX90614-xCx make this part highly suited in applications where secondary

heat sources can heat up the sensor. These sensors also have a very short stabilization time compared to

other types of thermopile sensors, which is of importance if one needs an accurate measurement in conditions

where the ambient temperature can change quickly.

 The MLX90614 supports versatile customization to a very wide range of temperatures, power supplies and

refresh rates.

 The user can program the internal object emissivity correction for objects with a low emissivity. An embedded

error checking and correction mechanism provides high memory reliability.

 The sensors are housed in an industry standard TO39 package for both single- and dual-zone IR thermometers.

The thermometer is available in automotive grade and can use two different packages for wider applications’

coverage.

 The low power consumption during operation and the low current draw during sleep mode make the

thermometer ideally suited for handheld mobile applications.

 The digital sensor interface can be either a power-up-and-measure PWM or an enhanced access SMBus

compatible protocol. Systems with more than 100 devices can be built with only two signal lines. Dual zone

non-contact temperature measurements are available via a single line (extended PWM).

 A build-in thermal relay function further extends the easy implementation of wide variety of freezing/boiling

prevention and alert systems, as well as thermostats (no MCU is needed).

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 34 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

10. Performance Graphs

10.1.

10.1.10.1.

10.1. Temperature accuracy of the MLX90614

Temperature accuracy of the MLX90614Temperature accuracy of the MLX90614

Temperature accuracy of the MLX90614

10.1.1.

10.1.1.10.1.1.

10.1.1. Standard accuracy

Standard accuracyStandard accuracy

Standard accuracy

Figure 22: Accuracy of MLX90614 (Ta, To) except for xCK type

±1°C

±2°C

±1°C

±2°C

±1°C

±2°C

±3°C

±2°C

±1°C

±2°C

±0.5°C

To, °C

0100

±3°C

-40

0

60

Ta, °C

±3°C

±1°C

12550

±4°C

±3°C

120

±4°C

180

240

300

±4°C

380

-20

±2°C±3°C

±3°C ±2°C

±4°C

±3°C

-40

-70

±3°C

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 35 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Figure 23 Accuracy of MLX90614xCK (Ta, To) only

All accuracy specifications apply under settled isothermal co23nditions only. Furthermore, the accuracy is only valid if the

object fills the FOV of the sensor completely.

±2°C

±3°C

±2°C

±3°C

±2°C

±3°C

±4°C

±3°C

±2°C

±2°C±0.75°C

To, °C

0100

±4°C

-40

0

60

Ta, °C

±4°C

±2°C

12550

±10°C

±4°C

120

±10°C

180

240

300

380

-20

±3°C±4°C

±4°C ±3°C

±10°C

±4°C

-40

-70

±4°C

±2.5°C

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 36 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

10.1.2.

10.1.2.10.1.2.

10.1.2. Medical accuracy

Medical accuracyMedical accuracy

Medical accuracy

A version of the MLX90614 with accuracy suited for medical applications is available. The accuracy in the range

Ta 16°C…40°C and To 22°C…40°C is shown in diagram below. The accuracy for the rest of the temperature ranges is the same

as in previous diagram. Medical accuracy specification is only available for the MLX90614Dxx versions.

Figure 24: Accuracy of MLX90614DAA (Ta, To) for medical applications.

Accuracy of the MLX90614DCC, DCH and DCI for VDD = 3V (see paragraph 10.1.3)

Versions MLX90614ESF-DCC, -DCH and -DCI comply with ASTM standard section 5.4 (Designation: E1965 – 98 (Re-approved

2009) - Standard Specification for Infrared Thermometers for Intermittent Determination of Patient Temperature

It is very important for the application designer to understand that the accuracy specified in Figure 22 and Figure 24 are only

guaranteed when the sensor is in thermal equilibrium and under isothermal conditions (there are no temperature

differences across the sensor package). The accuracy of the thermometer can be influenced by temperature differences in

the package induced by causes like (among others): Hot electronics (heaters / coolers) behind or beside the sensor or when

the measured object is so close to the sensor that heats the thermometer package.

This effect is especially relevant for thermometers with a small Field Of View (FOV) like the xxC and xxF as the energy

received by the sensor from the object is reduced. Therefore, Melexis has introduced the xCx version of the MLX90614. In

these MLX90614xCx, the thermal gradients are measured internally and the measured temperature is compensated for

them. In this way, the MLX90614xCx is much less sensitive to thermal gradients induced from outside, but the effect is not

totally eliminated. It is therefore important to avoid introducing strong heat sources close to the sensor or to shield the

sensor from them.

NOTE: In order to have the highest possible signal and the best performance a higher gain of the amplifier is selected for

MLX90614DCx type of devices. This eventually would limit the maximum object temperature (due to overload of the ADC) to

about 200°C.

10.1.3.

10.1.3.10.1.3.

10.1.3. Temperature reading dependence on VDD

Temperature reading dependence on VDDTemperature reading dependence on VDD

Temperature reading dependence on VDD

In case of medical applications where high accuracy is required and the supply is provided by means of a battery, a

compensation of temperature readings from VDD dependence should be done by the microcontroller. The dependence is

very repeatable and compensation can easily be implemented. As this dependence comes from the ambient temperature it

is the same for all type of devices regardless of FOV and optics used and it directly translates in the same compensation for

object temperature.

The typical VDD dependence of the ambient and object temperature is 0.6°C/V.

± 0.3°C

10

± 0.2°C

36

38

40

20 30 40

± 0.3°C

To, °C

Ta, °C

20

30

22

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 37 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Figure 25: Typical Ta dependence from supply voltage

Example: As the devices are calibrated at VDD=3V the error at VDD=3V is smallest one. The error in ambient channel is

directly transferred as object channel error (see Figure 26 below).

Figure 26: Typical To dependence from supply voltage (practically the same as Ta dependence error

In order to compensate for this error we measure supply voltage and by applying following equation compensate the result.

6.0)3(_)(

0_

×−−=×−−= VDDTdependenceTypicalVDDVDDTT

OOdcompensateO

Figure 27: Typical To compensated dependence error

Typical Ta=f(VDD) dependance

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0.40

0.50

2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8

VDD, V

Ta error, DegC

Sensor1

Sensor2

Sensor3

Sensor4

Sensor5

Sensor6

Sensor7

Sensor8

Sensor9

Sensor10

Sensor11

Sensor12

Sensor13

Sensor14

Sensor15

Sensor16

Typical To=f(VDD) dependance

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0.40

0.50

2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8

VDD, V

To error, DegC

Sensor1

Sensor2

Sensor3

Sensor4

Sensor5

Sensor6

Sensor7

Sensor8

Sensor9

Sensor10

Sensor11

Sensor12

Sensor13

Sensor14

Sensor15

Sensor16

Compensated VDD dependence

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8

VDD, V

To_compensated error, degC

Sensor1

Sensor2

Sensor3

Sensor4

Sensor5

Sensor6

Sensor7

Sensor8

Sensor9

Sensor10

Sensor11

Sensor12

Sensor13

Sensor14

Sensor15

Sensor16

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 38 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

10.2.

10.2.10.2.

10.2. Field Of View (FOV)

Field Of View (FOV)Field Of View (FOV)

Field Of View (FOV)

Figure 28: Field Of View measurement

Parameter Type xAA Type xBA Type xCC Type xCF Type xCH Type xCI Type xCK

Peak zone 1 0° +25° 0° 0° 0° 0° 0°

Width zone 1 90° 70° 35° 10° 12° 5° 13°

Peak zone 2 Not applicable -25° Not

applicable

Not

applicable Not applicable Not

applicable

Not

applicable

Width zone 2 70°

Table 14: FOV summary table

Figure 29: Typical FOV of MLX90614xAA

Point heat source

Rotated sensor

Angle of incidence

100%

50%

Sensitivity

Field Of View

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 39 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Figure 30: Typical FOV of MLX90614xBA Figure 31: Identification of zone

1&2 relative to alignment tab

Figure 32: Typical FOV of MLX90614xCC

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 40 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Figure 33: Typical FOV of MLX90614xCF

Figure 34: Typical FOV of MLX90614xCH

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 41 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Figure 35: Typical FOV of MLX90614xCI

Figure 36 Typical FOV of MLX90614xCK type

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 42 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

11. Applications Information

11.1.

11.1.11.1.

11.1. Use of the MLX90614 thermometer in

Use of the MLX90614 thermometer in Use of the MLX90614 thermometer in

Use of the MLX90614 thermometer in SMBus configuration

SMBus configurationSMBus configuration

SMBus configuration

Figure 37: MLX90614 SMBus connection

Figure 37 shows the connection of a MLX90614 to a SMBus with 3.3V power supply. The MLX90614 has diode clamps SDA /

SCL to Vdd so it is necessary MLX90614 to be powered in order not to load the SMBus lines.

11.2.

11.2.11.2.

11.2. Use of multiple MLX90614s in SMBus configuration

Use of multiple MLX90614s in SMBus configurationUse of multiple MLX90614s in SMBus configuration

Use of multiple MLX90614s in SMBus configuration

Figure 38: Use of multiple MLX90614 devices in SMBus network

The MLX90614 supports a 7-bit slave address in EEPROM, thus allowing up to 127 devices to be read via two common wires.

With the MLX90614xBx this results in 254 object temperatures measured remotely and an additional 127 ambient

temperatures which are also available. Current source pull-ups may be preferred with higher capacitive loading on the bus

(C3 and C4 represent the lines’ parasitic), while simple resistive pull-ups provide the obvious low cost advantage.

11.3.

11.3.11.3.

11.3. PWM output operation

PWM output operationPWM output operation

PWM output operation

Using the PWM output mode of the MLX90614 is very simple, as shown in Figure 39.

SCL

Vz

Vdd

R2

2

C1

0.1uF

3

U1 MCU

SCL

SDA

GND

Vdd

4

+3.3V

P W M

SDA

U2 MLX90614Bxx

R1

1

SMBus

Vss

R2

U1 MLX90614Bxx

4

1

2

SCL

Vz

U1 MLX90614Bxx

C4

Cbus2

U1 MCU

SCL

SDA

GND

Vdd

1

I1

Ipu1

C2

0.1uF

SCL

Vz

3

SDA

C3

Cbus1

R1

3

SCL

4

C1

0.1uF

Vss

+3.3V

I2

Ipu2

Vdd

2

SMBus

Vss

Current source or resistor

pull-ups of the bus

P W M

SDA

P W M

SDA

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 43 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

Figure 39: Connection of MLX90614 for PWM output mode

The PWM mode is free-running after POR when configured in EEPROM. The SCL pin must be forced high for PWM mode

operation (can be shorted to V

DD

pin).

A pull-up resistor can be used to preserve the option for SMBus operation while having PWM as a default as is shown on

Figure 40.

Figure 40: PWM output with SMBus available

Again, the PWM mode needs to be written as the POR default in EEPROM. Then for PWM operation the SCL line can be high

impedance, forced high, or even not connected. The pull-up resistor R1 will ensure there is a high level on the SCL pin and

the PWM POR default will be active. SMBus is still available (for example – for further reconfiguration of the MLX90614, or

sleep mode power management) as there are pull-up resistors on the SMBus lines anyway.

PWM can be configured as open drain NMOS or a push-pull output. In the case of open drain external pull-up will be needed.

This allows cheap level conversion to lower logic high voltage. Internal pull-ups present in many MCUs can also be used.

11.4.

11.4.11.4.

11.4. Thermal alert / thermostat

Thermal alert / thermostatThermal alert / thermostat

Thermal alert / thermostat

Figure 41: Thermal alert / thermostat applications of MLX90614

The MLX90614 can be configured in EEPROM to operate as a thermal relay. A non-contact freezing or boiling prevention

with 1 mA quiescent current can be built with two components only – the MLX90614 and a capacitor. The PWM / SDA pin

can be programmed as a push-pull or open drain NMOS, which can trigger an external device, such as a relay (refer to

electrical specifications for load capability), buzzer, RF transmitter or a LED. This feature allows very simple thermostats to

be built without the need of any MCU and zero design overhead required for firmware development. In conjunction with a

MCU, this function can operate as a system alert that wakes up the MCU. Both object temperature and sensor die

temperature can also be read in this configuration.

J1

CON1

PWM

Vdd

GND

2

0.1uF

Vdd U1

MLX90614

Vss

P W M

SDA

1

C1

SCL

Vz

3

P W M

SDA

10k

3

1

Vdd

2

R1

SCL

Vz

J1

CON1

SCL

PWM/SDA

GND

Vdd

U1

MLX90614

Vss

0.1uF

C1

U2

AC line

R1

3

C2

10uF

C1

0.1uF

U1 MCU

SCL

SDA

GND

Vdd

2

SCL

Vz

C*

2

SCL

Vz

U1

MLX90614Axx

U1 MLX 90614Bxx

Vss

Vdd

1 1

SMBus

R2

Vdd

4

Q1

4

1

+5V

U1 MLX90614A xx

Vdd

Vss

+3.3V R1

C3

0.1uF

SCL

Vz

3

R2

+24V

Vss

C1

0.1uF

P W M

SDA

P W M

SDA

3

4

P W M

SDA

D1

Alert dev ice

+

-

2

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 44 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

11.5.

11.5.11.5.

11.5. High voltage source operation

High voltage source operationHigh voltage source operation

High voltage source operation

As a standard, the module MLX90614Axx works with a supply voltage of 5Volt. In addition, thanks to the integrated internal

reference regulator available at pin SCL / Vz, this module can easily be powered from higher voltage source (like

VDD=8…16V). Only a few external components as depicted in the diagram below are required to achieve this.

Figure 42: 12V regulator implementation

With the second (synthesized Zener diode) function of the SCL / Vz pin used, the 2-wire interface function is available only if

the voltage regulator is overdriven (5V regulated power is forced to Vdd pin).

2.2uF

1

Vdd

Vss

P W M

SDA

U1

5.7V

C* +12V

J1

CON1

PWM

V+

GND

3

Equivalent schematics

Q1

U1

MLX90614

2

C1

SCL

Vz

MLX90614Axx: V=8...16V

+5V

4

R1

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 45 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

12. Application Comments

Significant contamination at the optical input side (sensor filter) might cause unknown additional filtering/distortion of the

optical signal and therefore result in unspecified errors.

IR sensors are inherently susceptible to errors caused by thermal gradients. There are physical reasons for these phenomena

and, in spite of the careful design of the MLX90614, it is recommended not to subject the MLX90614 to heat transfer and

especially transient conditions.

Upon power-up the MLX90614 passes embedded checking and calibration routines. During these routines the output is not

defined and it is recommended to wait for the specified POR time before reading the module. Very slow power-up may

cause the embedded POR circuitry to trigger on inappropriate levels, resulting in unspecified operation and this is not

recommended.

The MLX90614 is designed and calibrated to operate as a non-contact thermometer in settled conditions. Using the

thermometer in a very different way will result in unknown results.

Capacitive loading on a SMBus can degrade the communication. Some improvement is possible with use of current sources

compared to resistors in pull-up circuitry. Further improvement is possible with specialized commercially available bus

accelerators. With the MLX90614 additional improvement is possible by increasing the pull-up current (decreasing the pull-

up resistor values). Input levels for SMBus compatible mode have higher overall tolerance than the SMBus specification, but

the output low level is rather low even with the high-power SMBus specification for pull-up currents. Another option might

be to go for a slower communication (clock speed), as the MLX90614 implements Schmidt triggers on its inputs in SMBus

compatible mode and is therefore not really sensitive to rise time of the bus (it is more likely the rise time to be an issue

than the fall time, as far as the SMBus systems are open drain with pull-up).

For ESD protection there are clamp diodes between the Vss and Vdd and each of the other pins. This means that the

MLX90614 might draw current from a bus in case the SCL and/or SDA is connected and the Vdd is lower than the bus pull-

ups’ voltage.

In 12V powered systems SMBus usage is constrained because the SCL pin is used for the Zener diode function. Applications

where the supply is higher than 5V should use the PWM output or an external regulator. Nevertheless, in the 12V powered

applications MLX90614 can be programmed (configured and customized) by forcing the Vdd to 5V externally and running the

SMBus communication.

A sleep mode is available in the MLX90614Bxx. This mode is entered and exited via the SMBus compatible 2-wire

communication. On the other hand, the extended functionality of the SCL pin yields in increased leakage current through

that pin. As a result, this pin needs to be forced low in sleep mode and the pull-up on the SCL line needs to be disabled in

order to keep the overall power drain in sleep mode really small. During sleep mode the sensor will not perform

measurements.

The PWM pin is not designed for direct drive of inductive loads (such as electro-magnetic relays). Some drivers need to be

implemented for higher load, and auxiliary protection might be necessary even for light but inductive loading.

It is possible to use the MLX90614 in applications, powered directly from the AC line (transformer less). In such cases it is

very important not to forget that the metal package of the sensor is not isolated and therefore may occur to be connected

to that line, too. Melexis cannot be responsible for any application like this and highly recommends not using the MLX90614

in that way.

Power dissipation within the package may affect performance in two ways: by heating the “ambient” sensitive element

significantly beyond the actual ambient temperature, as well as by causing gradients over the package that will inherently

cause thermal gradient over the cap. Loading the outputs also causes increased power dissipation. In case of using the

MLX90614Axx internal Zener voltage feature, the regulating external transistor should also not cause heating of the TO39

package.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 46 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

High capacitive load on a PWM line will result in significant charging currents from the power supply, bypassing the

capacitor and therefore causing EMC, noise, level degradation and power dissipation problems. A simple option is adding a

series resistor between the PWM / SDA pin and the capacitive loaded line, in which case timing specifications have to be

carefully reviewed. For example, with a PWM output that is set to 1.024 ms and the output format that is 11 bit, the time

step is 0.5 μs and a settling time of 2 μs would introduce a 4 LSB error.

Power supply decoupling capacitor is needed as with most integrated circuits. MLX90614 is a mixed-signal device with

sensors, small signal analog part, digital part and I/O circuitry. In order to keep the noise low power supply switching noise

needs to be decoupled. High noise from external circuitry can also affect noise performance of the device. In many

applications a 100nF SMD ceramic capacitor close to the Vdd and Vss pins would be a good choice. It should be noted that

not only the trace to the Vdd pin needs to be short, but also the one to the Vss pin. Using MLX90614 with short pins

improves the effect of the power supply decoupling.

Severe noise can also be coupled within the package from the SCL (in worst cases also from the SDA) pin. This issue can be

solved by using PWM output. Also the PWM output can pass additional filtering (at lower PWM frequency settings). With a

simple LPF RC network added also increase of the ESD rating is possible.

Check www.melexis.com for most recent application notes about MLX90614.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 47 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

13. Standard information regarding manufacturability of Melexis products

with different soldering processes

Our products are classified and qualified regarding soldering technology, solderability and moisture sensitivity level

according to following test methods:

Wave Soldering THD’s (Through Hole Devices)

• EIA/JEDEC JESD22-B106 and EN60749-15

Resistance to soldering temperature for through-hole mounted devices

Iron Soldering THD’s (Through Hole Devices)

• EN60749-15

Resistance to soldering temperature for through-hole mounted devices

Solderability THD’s (Through Hole Devices)

• EIA/JEDEC JESD22-B102 and EN60749-21

Solderability

For all soldering technologies deviating from above mentioned standard conditions (regarding peak temperature,

temperature gradient, temperature profile etc) additional classification and qualification tests have to be agreed upon with

Melexis.

Melexis is contributing to global environmental conservation by promoting lead free solutions. For more information on

qualifications of RoHS compliant products (RoHS = European directive on the Restriction Of the use of certain Hazardous

Substances) please visit the quality page on our website: http://www.melexis.com/quality.aspx

The MLX90614 is RoHS compliant

14. ESD Precautions

Electronic semiconductor products are sensitive to Electro Static Discharge (ESD).

Always observe Electro Static Discharge control procedures whenever handling semiconductor products.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 48 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

15. FAQ

When I measure aluminum and plastic parts settled at the same conditions I get significant errors on aluminum.

Why?

Different materials have different emissivity. A typical value for aluminum (roughly polished) is 0.18 and for plastics values

of 0.84…0.95 are typical. IR thermometers use the radiation flux between the sensitive element in the sensor and the object

of interest, given by the equation

( ) ( )

2

4

221

4

111

ATFATq

ba

×××−×××××=

−

σεσαε

,

Where:

ε

1

and ε

2

are the emissivities of the two objects,

α

1

is the absorptivity of the sensor (in this case),

σ is the Stefan-Boltzmann constant,

A

1

and A

2

are the surface areas involved in the radiation heat transfer,

F

a-b

is the shape factor,

T

1

and T

2

are known temperature of the sensor die (measured with specially integrated and calibrated element) and the

object temperature that we need.

Note that these are all in Kelvin, heat exchange knows only physics.

When a body with low emissivity (such as aluminum) is involved in this heat transfer, the portion of the radiation incident to

the sensor element that really comes from the object of interest decreases – and the reflected environmental IR emissions

take place. (This is all for bodies with zero transparency in the IR band.) The IR thermometer is calibrated to stay within

specified accuracy – but it has no way to separate the incoming IR radiation into real object and reflected environmental

part. Therefore, measuring objects with low emissivity is a very sophisticated issue and infra-red measurements of such

materials are a specialized field.

What can be done to solve that problem? Look at paintings – for example, oil paints are likely to have emissivity of

0.85…0.95 – but keep in mind that the stability of the paint emissivity has inevitable impact on measurements.

It is also a good point to keep in mind that not everything that looks black is “black” also for IR. For example, even heavily

oxidized aluminum has still emissivity as low as 0.30.

How high is enough? Not an easy question – but, in all cases the closer you need to get to the real object temperature the

higher the needed emissivity will be, of course.

With the real life emissivity values the environmental IR comes into play via the reflectivity of the object (the sum of

Emissivity, Reflectivity and Absorptivity gives 1.00 for any material). The larger the difference between environmental and

object temperature is at given reflectivity (with an opaque for IR material reflectivity equals 1.00 minus emissivity) the bigger

errors it produces.

After I put the MLX90614 in the dashboard I start getting errors larger than specified in spite that the module was working

properly before that. Why?

Any object present in the FOV of the module provides IR signal. It is actually possible to introduce error in the measurements

if the module is attached to the dashboard with an opening that enters the FOV. In that case portion of the dashboard

opening will introduce IR signal in conjunction with constraining the effective FOV and thus compromising specified

accuracy. Relevant opening that takes in account the FOV is a must for accurate measurements. Note that the basic FOV

specification takes 50% of IR signal as threshold (in order to define the area, where the measurements are relevant), while

the entire FOV at lower level is capable of introducing lateral IR signal under many conditions.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 49 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

When a hot (cold) air stream hits my MLX90614 some error adds to the measured temperature I read. What is it?

IR sensors are inherently sensitive to difference in temperatures between the sensitive element and everything incident to

that element. As a matter of fact, this element is not the sensor package, but the sensor die inside. Therefore, a thermal

gradient over the sensor package will inevitably result in additional IR flux between the sensor package and the sensor die.

This is real optical signal that can not be segregated from the target IR signal and will add errors to the measured

temperature.

Thermal gradients with impact of that kind are likely to appear during transient conditions. The sensor used is developed

with care about sensitivity to this kind of lateral phenomena, but their nature demands some care when choosing place to

use the MLX90614 in order to make them negligible.

I measure human body temperature and I often get measurements that significantly differ from the +37°C I expect.

IR measurements are true surface temperature measurements. In many applications this means that the actual temperature

measured by an IR thermometer will be temperature of the clothing and not the skin temperature. Emissivity (explained first

in this section) is another issue with clothes that has to be considered.

There is also the simple chance that the measured temperature is adequate – for example, in a cold winter human hand can

appear at temperatures not too close to the well-known +37°C.

I consider using MLX90614AAA to measure temperature within car compartment, but I am embarrassed about the Sun

light that may hit the module. Is it a significant issue?

Special care is taken to cut off the visible light spectra as well as the NIR (near IR) before it reaches the sensitive sensor die.

Even more, the glass (in most cases) is not transparent to the IR radiation used by the MLX90614. Glass has temperature and

really high emissivity in most cases – it is “black” for IR of interest. Overall, Sun behind a window is most likely to introduce

relatively small errors. Why is it not completely eliminated after all? Even visible light partially absorbed in the filter of the

sensor has some heating potential and there is no way that the sensor die will be “blind” for that heating right in front of it.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 50 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

16. Package Information

16.1.

16.1.16.1.

16.1. MLX90614xxA

MLX90614xxAMLX90614xxA

MLX90614xxA

The MLX90614 is packaged in an industry standard TO39 can.

Figure 43: MLX90614xxA package

Note: All dimensions are in mm

16.2.

16.2.16.2.

16.2. MLX90614xCC

MLX90614xCCMLX90614xCC

MLX90614xCC

Figure 44: MLX90614xCC package

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 51 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

16.3.

16.3.16.3.

16.3. MLX90614xCF

MLX90614xCFMLX90614xCF

MLX90614xCF

Figure 45: MLX90614xCF package

16.4.

16.4.16.4.

16.4. MLX90614xCH

MLX90614xCHMLX90614xCH

MLX90614xCH

Figure 46: MLX90614xCH package

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 52 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

16.5.

16.5.16.5.

16.5. MLX90614xCI

MLX90614xCIMLX90614xCI

MLX90614xCI

Figure 47: MLX90614xCI package

16.6.

16.6.16.6.

16.6. MLX90614xCK

MLX90614xCKMLX90614xCK

MLX90614xCK

Figure 48 MLX90614xCK package

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 53 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

16.7.

16.7.16.7.

16.7. Part marking

Part markingPart marking

Part marking

The MLX90614 is laser marked with 10 symbols. First 3 letters define device version (AAA, BCC, etc), and the last 7 are

the lot number. Example: “ACC9307308” – MLX90614ACC from lot 9307308.

16.8.

16.8.16.8.

16.8. Operating and storage humidity range

Operating and storage humidity rangeOperating and storage humidity range

Operating and storage humidity range

Operating and storage humidity range is defined as 85% non-condensing humidity.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 54 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

17. Table of figures

Figure 1: Typical application schematics ..................................................................................................................................... 2

Figure 2: Pin description ............................................................................................................................................................ 8

Figure 3: Block diagram ........................................................................................................................................................... 13

Figure 4: SMBus packet element key ........................................................................................................................................ 18

Figure 5: SMBus read word format ........................................................................................................................................... 19

Figure 6: SMBus write word format .......................................................................................................................................... 19

Figure 7: Recommended timing on SMBus................................................................................................................................ 19

Figure 8: Read word format (SA=0x5A, read RAM=0x07, result=0x3AD2, PEC=0x30) .................................................................. 20

Figure 9: Write word format (SA=0x5A, write EEPROM=0x02, data=0xC807, PEC=0x48) ............................................................ 20

Figure 10: SMBus timing specification and definition ................................................................................................................ 21

Figure 11: Enter sleep mode command (SA = 0x5A, Command = 0xFF, PEC = 0xE8) .................................................................... 22

Figure 12: Exit Sleep Mode ...................................................................................................................................................... 22

Figure 13: Undershoot of SCL line due to on chip synthesized Zener diode (5V versions only) ................................................... 23

Figure 14: PWM timing single (above) and extended PWM (bellow).......................................................................................... 24

Figure 15: PWM example single mode ...................................................................................................................................... 25

Figure 16: Extended PWM format with DUAL [5:1] = 01h (2 repetitions for each data) .............................................................. 26

Figure 17: Example: Extended PWM mode readings – sensor 1 above and sensor 2 bellow ...................................................... 26

Figure 18: Switching from PWM mode to SMBus ...................................................................................................................... 29

Figure 19: Request (switch to SMBus) condition ....................................................................................................................... 29

Figure 20: Software flow .......................................................................................................................................................... 32

Figure 21: Thermal relay: “PWM” pin versus Tobj ..................................................................................................................... 32

Figure 22: Accuracy of MLX90614 (Ta, To) except for xCK type ................................................................................................. 34

Figure 23 Accuracy of MLX90614xCK (Ta, To) only .................................................................................................................... 35

Figure 24: Accuracy of MLX90614DAA (Ta, To) for medical applications. Accuracy of the MLX90614DCC, DCH and DCI for VDD = 3V

(see paragraph 10.1.3) ............................................................................................................................................................. 36

Figure 25: Typical Ta dependence from supply voltage ............................................................................................................. 37

Figure 26: Typical To dependence from supply voltage (practically the same as Ta dependence error ....................................... 37

Figure 27: Typical To compensated dependence error .............................................................................................................. 37

Figure 28: Field Of View measurement ..................................................................................................................................... 38

Figure 29: Typical FOV of MLX90614xAA .................................................................................................................................. 38

Figure 30: Typical FOV of MLX90614xBA................................................................................................................................... 39

Figure 31: Identification of zone 1&2 relative to alignment tab................................................................................................. 39

Figure 32: Typical FOV of MLX90614xCC ................................................................................................................................... 39

Figure 33: Typical FOV of MLX90614xCF ................................................................................................................................... 40

Figure 34: Typical FOV of MLX90614xCH .................................................................................................................................. 40

Figure 35: Typical FOV of MLX90614xCI .................................................................................................................................... 41

Figure 36 Typical FOV of MLX90614xCK type ............................................................................................................................ 41

Figure 37: MLX90614 SMBus connection .................................................................................................................................. 42

Figure 38: Use of multiple MLX90614 devices in SMBus network .............................................................................................. 42

Figure 39: Connection of MLX90614 for PWM output mode ..................................................................................................... 43

Figure 40: PWM output with SMBus available .......................................................................................................................... 43

Figure 41: Thermal alert / thermostat applications of MLX90614 .............................................................................................. 43

Figure 42: 12V regulator implementation ................................................................................................................................. 44

Figure 43: MLX90614xxA package ............................................................................................................................................ 50

Figure 44: MLX90614xCC package ............................................................................................................................................ 50

Figure 45: MLX90614xCF package ............................................................................................................................................ 51

Figure 46: MLX90614xCH package ............................................................................................................................................ 51

Figure 47: MLX90614xCI package ............................................................................................................................................. 52

Figure 48 MLX90614xCK package ............................................................................................................................................. 52

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 55 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

18. References

[1] System Management Bus (SMBus) Specification Version 2.0 August 3, 2000

Duracell, Inc., Energizer Power Systems, Inc., Fujitsu, Ltd., Intel Corporation, Linear Technology

Inc., Maxim Integrated Products, Mitsubishi Electric Semiconductor Company, PowerSmart, Inc.,

Toshiba Battery Co. Ltd., Unitrode Corporation, USAR Systems, Inc.

MLX90614 family

Single and Dual Zone

Infra Red Thermometer in TO-39

Page 56 of 57

REVISION 11 - 20 NOVEMBER 2018

3901090614

19. Contact

For the latest version of this document, go to our website at www.melexis.com.

For additional information, please contact our Direct Sales team and get help for your specific needs:

Europe, Africa Telephone: +32 13 67 04 95

Email : sales_europe@melexis.com

Americas Telephone: +1 603 223 2362

Email : sales_usa@melexis.com

Asia Email : sales_asia@melexis.com

20. Disclaimer

The information furnished by Melexis herein (“Information”) is believed to be correct and accurate. Melexis disclaims (i) any and all liability in connection with or arising out of the

furnishing, performance or use of the technical data or use of the product(s) as described herein (“Product”) (ii) any and all liability, including without limitation, special,

consequential or incidental damages, and (iii) any and all warranties, express, statutory, implied, or by description, including warranties of fitness for particular purpose, non-

infringement and merchantability. No obligation or liability shall arise or flow out of Melexis’ rendering of technical or other services.

The Information is provided "as is” and Melexis reserves the right to change the Information at any time and without notice. Therefore, before placing orders and/or prior to

designing the Product into a system, users or any third party should obtain the latest version of the relevant information to verify that the information being relied upon is current.

Users or any third party must further determine the suitability of the Product for its application, including the level of reliability required and determine whether it is fit for a

particular purpose.

The Information is proprietary and/or confidential information of Melexis and the use thereof or anything described by the Information does not grant, explicitly or implicitly, to

any party any patent rights, licenses, or any other intellectual property rights.

This document as well as the Product(s) may be subject to export control regulations. Please be aware that export might require a prior authorization from competent authorities.

The Product(s) are intended for use in normal commercial applications. Unless otherwise agreed upon in writing, the Product(s) are not designed, authorized or warranted to be

suitable in applications requiring extended temperature range and/or unusual environmental requirements. High reliability applications, such as medical life-support or life-

sustaining equipment are specifically not recommended by Melexis.

The Product(s) may not be used for the following applications subject to export control regulations: the development, production, processing, operation, maintenance, storage,

recognition or proliferation of 1) chemical, biological or nuclear weapons, or for the development, production, maintenance or storage of missiles for such weapons: 2) civil

firearms, including spare parts or ammunition for such arms; 3) defense related products, or other material for military use or for law enforcement; 4) any applications that, alone

or in combination with other goods, substances or organisms could cause serious harm to persons or goods and that can be used as a means of violence in an armed conflict or any

similar violent situation.

The Products sold by Melexis are subject to the terms and conditions as specified in the Terms of Sale, which can be found at https://www.melexis.com/en/legal/terms-and-

conditions.

This document supersedes and replaces all prior information regarding the Product(s) and/or previous versions of this document.

ISO/TS 16949 and ISO14001 Certified